The Facebook detectives: Looking for Lisa Stone

Produced by Chuck Stevenson and Lucy Scott

[This story was first broadcast on May 7, 2011. It was updated on June 5, 2012.]

(CBS) DALLAS -- On a chilly night in Dallas, friends Tina Wiley, Tammye Markle and Joni Shannon are out trying to solve a mystery. They are looking for clues at the home of their old friend, Lisa Stone, who vanished without a trace last spring.

"For her to go missing for even one day is highly unusual and abnormal," Tammye tells "48 Hours Mystery" correspondent Maureen Maher. "We had to take matters into our own hands at that point... Somebody had to look for Lisa."

Lisa, 51, was last seen alive near her home in a Dallas suburb on June 5, 2010.

The search has taken her friends down memory lane... all the way to back to high school, where in the late 1970s, Lisa was a sexy, high-kicking cowgirl with the Mesquite High drill team.

Photos: Looking for Lisa Stone

The old friends had first gotten back together at a school reunion in 2009, where they reminisced about old times.

"We went out a lot on weekends to the disco - snuck in sometimes. We were a little underage," Tina recalls with a laugh. "She loved that... She loved to have a good time, and she loved to dance."

The women caught up and talked about how all of their lives had gone in very different directions.

Joni Shannon was a home maker with a Harley and Tammye Markle had spent a lot of her life coaching beauty pageant contestants.

Tina Wiley spent years managing a construction business. Away from work, she had become obsessed with Facebook.

"She thought I was "The Facebook Queen," she says of Lisa. "She thought I was the expert."

Lisa Stone had been in newspaper ad sales until she lost her job in 2006. She, too, was a huge Facebook fan.

"I think that Facebook made her feel very young. I think she could relive her youth," says Tina.

After the reunion, they used Facebook to keep in touch.

Asked about Lisa's personality on Facebook - whether she was private or "let it all hang out" - her friends say, "You knew everything, every detail of her life."

One detail everyone knew was that Lisa Stone loved to be loved.

"She always had a very strong desire to be loved," says Tammye.

"She was very insecure actually...she was always looking for acceptance," says Tina.

"I think that need to be loved caused her to overlook a lot of things," adds Tammye.

Lisa grew up in a wonderful family. Her father was a Dallas cop; her mother, a homemaker, took care of Lisa, her two brothers and an older sister.

But Lisa's cheerful spirit had taken a beating over the years, battered by tragedy after tragedy. Her sister had been killed in a car crash, her beloved brother, Dennis, died of AIDS and her mother died of cancer. In 2005, her father, with whom she had been living and caring for, passed away.

"There were a lot of people that were very concerned for Lisa," Tina tells Maher. "It just seemed things were just spiraling down for her..."

The loss of her brother Dennis, who was gay, cut especially close.

"Growing up in Mesquite in the 70s - it was very conservative. You didn't discuss such things," says Tina.

It wasn't until that high school reunion that Lisa finally discussed her own secret.

"At the party she passed around this little souvenir she had from Six Flags and it had a picture of her partner," Tina says. "That's kind of how she told people there."

"She was expecting, I think, when she passed around that picture, people would go 'your partner? You mean you're gay?' And everyone went 'that's nice,'" says Tammye.

The woman in the picture was Sherry Henry.

"...Lisa is my partner of 15 plus years," she tells Maher. "When I first met Lisa, I walked into the club and she was across the way. And our eyes met (laughs)... She came over and started chatting with me and we hit it off."

Sherry says they became a couple "almost immediately."

"Were you in love with her?" Maher asks.

"Very much," says Sherry.

"And she was in love with you?"

"I would hope," she replies with a laugh.

After Lisa's dad died in 2005, Sherry came around more and more, eventually moving in in 2009.

Asked if she considered herself married, Sherry says, 'Yes."

As a couple, she says hey shared a lot. "We grew up both in the Midwest - strong family values," says Sherry.

And apparently, Lisa happily shared a $300,000 inheritance with Sherry.

Friends say the couple lived off the inheritance until early 2010, when Lisa suddenly realized she was broke.

"One day she came to me and just said she was out of money," Sherry tells Maher.

"Was that surprising to you?"

"Extremely surprising."

In early June 2010, the relationship between Sherry and Lisa came to an end - an abrupt end - when, according to her friends, Lisa vanished.

"I noticed I hadn't talked with her in about two weeks," says Tina.

There were no postings on Facebook and no photos. There was nothing for days from the woman who never skipped a single day on the social media site.

"So I immediately got on the phone and started calling Sherry," Tina says. "She kept giving me different stories right away: 'Lisa's off doing odd jobs.' And like late at night. So immediately I started contacting Joni and Tammye."

"When you told me 'Lisa is missing. She hasn't been heard from in a few weeks,' I immediately knew--my heart started pounding," Tammye says to Tina.

"And that's when all of us just got involved trying to piece this thing together," says Tina.

Sherry says there's nothing to piece together.

Asked if she filed a missing persons report, Sherry says, "No, I did not."

"Was there ever a time when you thought, that as her life partner, that you should file a missing persons report?" Maher asks.

"No I did not," Sherry replies. "At the time, prior to me leaving Dallas, Lisa Stone is not missing."

Joni Shannon, Tammye Markle and Tina Wiley believe their friend, Lisa Stone, vanished on the first weekend of June 2010. On Saturday, June 5, Lisa's regular daily Facebook postings just stopped.

"I called her cell phone and it was disconnected," says Tina.

"I'm sick to my stomach, something's wrong," adds Tammye.

That very same day also appears to be the last day anyone physically saw Lisa Stone.

"It was the 5th that Lisa was over here," says neighbor Juanita Burris. It was also the last time she says she saw Lisa.

Juanita lives two doors down from Lisa, and says on that on Saturday, Lisa came calling just like clockwork.

"I think she depended on me for advice," she tells Maureen Maher. "She would come over here and sit in that chair...She was always around. She was in the yard or she was at your house or she was calling you. ...You could look out and you could see Lisa."

Juanita says a day didn't go by that that she didn't see Lisa.

The two women chatted that Saturday night and Lisa promised to return the next day to take out Juanita's garbage. Lisa never showed up.

"Sherry called me the next day, which was very unusual," she says. "She called me and she said Lisa's having a gallbladder attack and she said she's lying down. Then she said she could come over and take it out. And I said that'd be fine. And she never - she's been over here maybe one time."

"One time in how many years?" Maher asks.

"The whole time she was over there," Juanita replies.

Three days later, on June 9, there was another curious development: Joni got a hit on her Facebook page. "I knew it wasn't Lisa because of the way it was worded. It said, 'Joni, how are you and family?'" she says.

Lisa's Facebook page, which had been eerily dormant for three days, lit up again. But the ladies say they're sure it was not Lisa who sent the message.

She never talked to me like that," Joni explains. "She'd say, 'Tell Steve hi' or 'How is Steve?' She always said his name. Not 'how are you and family?'"

"What was your first reaction when you read it," Maher asks. "Were you at all relived?"

"No," Joni replies, "'cause I knew it was Sherry."

Sherry says she's never even been on Facebook.

"I don't know how to log on....I don't know anything about Facebook," she tells Maher.

Ten days later, Juanita Burris was worried enough to go to the Dallas police to file a missing persons report.

"Well, he said, 'Oh, she's probably just somewhere. She'll be back,'" Juanita says of the police reaction. "And I said, 'Something has happened to her.'"

Asked if she thought the police took her report seriously, Juanita says, "No. They thought I didn't know what I was talking about."

Within two days, on June 21, a detective did stop by Lisa's house. Sherry told the officer there was nothing to worry about. Lisa was simply away.

"They just accepted that as the truth and closed the file," says Tammye.

"We didn't feel like the police were responding," adds Tina.

The Facebook friends called Sherry repeatedly to ask where Lisa was.

"Everyday I was told a different story," Tina says. "Every day, Lisa was off here, Lisa was off there..."

For example, Sherry told the ladies that Lisa was working odd jobs for friend Pat James - helping her in the garden.

"I had hand surgery and I couldn't do a lot of work in the garden, so I hired her and she'd come over every morning around nine and she'd stay till about five," says Pat.

But that was in May, well before Lisa disappeared.

"I was in Florida three weeks and Lisa's friends, Tammye and Tina, they both called me in Florida - they had tracked me down, and I says, 'What's up?' 'Well, Lisa's disappeared.' And I said, 'disappeared?'"

Finally, on June 29, terrified that something truly awful had happened to Lisa, Joni and Tina confronted Sherry.

"Joni and I went there one night...Sherry let us in," Tina explains. "And we sat down and talked for an hour and a half."

"She said, 'Oh...Lisa's working, she's on her way home and I've ordered us a pizza,' and this was like 8 p.m.," Joni recalls.

"What did she tell you?" Maher asks the women.

"Nothing," says Tina

"Did you think Lisa was coming home?"

"No."

Eventually, the ladies just left. But Sherry says actually, they never showed up.

"Did any of her high school friends come over in June and say we want to see her? And you said according to them: "She's on her way home, I've ordered a pizza, you can come in and wait for her." Did that ever happen?" Maher asks Sherry.

"No," she replies.

"It never happened?"

"No."

"They're adamant that they came over to the house..."

"They can be as adamant as they want to."

Almost a month after Lisa was last seen, Joni says she decided to surprise Sherry and swing by Lisa's house again. And that led to an unbelievable chance encounter.

Joni sent Tina a text as she drove into Lisa's neighborhood.

"Joni said she was gonna go by the house and see if she came home with Lisa," Tina recalls, "so I was just about to type when Joni called me."

"'Tina... guess what? Sherry is driving Lisa's car and sitting beside me at a red light,'" Joni says of her call to Tina.

Asked if Sherry noticed her, Joni says, "No. And I panicked for a moment because I couldn't believe this. I was like, 'Oh my goodness.' I said, 'Oh my gosh... what do I do?' And she said, 'Follow her!'

"So I followed Sherry," she continues. "She pulled into a 7-Eleven parking lot... she pulls in front of the dumpster... I pull behind the gas pump and just get out of the car...and I'm hiding behind the pump, watching her and she proceeded to open up the trunk and started pulling out baskets and a little suitcase and proceeded to throw them into the trash dumpster."

In the dumpster, Joni says she found a suitcase full of Lisa's most personal belongings.

"...Lisa's birth certificate was in there. Her deceased brother Dennis - his death certificate was in there. Bibles," Joni says. "Just real precious personal things she would not have disposed of."

Why would Sherry dump Lisa's belongings? Sherry says she didn't.

"We'll here's what I'll tell you about the dumpster incident... There is no dumpster incident," says Sherry.

"When you say there was no dumpster incident, do you deny that you threw a blue suitcase full of personal items inside the dumpster?" Maher asks.

"Absolutely."

"You were never there?"

"Not true."

"It's all a flat out lie?"

"Flat out lie..."

The ladies had had it.

"I just thought that nothing she had told me had been true," says Tina.

Armed with evidence from the dumpster and a timeline of events, on July 3, the women marched into police headquarters and demanded action.

Joni says, "We met at the Dallas police downtown office...and walked in the front door and said, 'You're gonna listen to us.'"

The cops agreed to take another look. But that didn't mean the ladies were about to let go of their own investigation. They tapped into the power of Facebook, asking Lisa's Facebook friends for any information that might help them find her.

It worked. One of the strongest Facebook clues led them to a creek bed near Lisa's house - the same place where Sherry Henry was seen running and covered in mud.

As the ladies worked the case, Tina Wiley, the "Facebook Queen," took command.

"Anything that comes along...we check it out," she says. "So we checked a couple of areas that people gave us a tip."

They put up a billboard, raised money for a $10,000 reward and created a Facebook page dedicated exclusively to finding Lisa Stone.

One Facebook clue led them to a muddy creek bed not far from Lisa's house. According to the tip, Lisa's girlfriend, Sherry Henry, was seen in the area covered with mud several weeks after Lisa disappeared.

Video: Witness on seeing Sherry Henry

"Sherry was described as muddy or very dirty," says Tina.

Sherry actually admits she was in the creek.

"That was [the] day I was surrounded by at least 10 to 15 women... in their SUVs trying to track me down," she tells Maher. "And I felt like I was a rabbit being chased for the hunt."

That very same day, Sherry says a group of unidentified women started to stalk and harass her.

"I come home...when I come around the back alley and go through the gate... I see the blinds part," she says. "Inside the house. So I get a little freaked... I'm thinking, 'there's somebody's in the house....' Now you tell me, you wouldn't be scared for that?"

Sherri says she ran for her life... and that's how she ended up in the creek.

"I'm afraid," she says. "I went around through the woods...off of that creek area."

The women, who began calling themselves "the Facebook detectives," deny they ever chased Sherry into the creek that day or broke into her house, but agree they've been watching her closely.

"At some point, did she accuse all of you of stalking her?" Maher ask the ladies.

"Yes," they reply with laughter.

Sherry went to the police. In fact, the Dallas police did warn the women to back off after Sherry complained about them.

"Has anyone in the group - the whole group of the women - ever, maybe, crossed the line in terms of looking for evidence?" Maher asks the ladies.

"No," and "I don't really think so," they say in unison.

Sherry isn't about to back down from a fight with the Facebook detectives.

"My issue is with three or four people out there - Tina Wiley, Joni Shannon and Tammy Markel," Sherry says. "You will not tear down my life. You will not point the finger at me until you have verifiable proof that I have ever done anything other than support Lisa Stone in whatever she wanted to accomplish in her life. Lisa and I love each other...end of discussion."

To hear Sherry Henry tell the story, Lisa's friends knew nothing of her real-life drama.

"You're on Facebook...but yet you claim you're a really good friend of Lisa," says Sherry.

"So are you saying she didn't really have a relationship with those women?" Maher asks.

"I know she didn't."

According to Sherry, there's a lot about Lisa that the Facebook detectives don't know, starting with insurmountable money problems when the inheritance ran out. There was also a life-long battle with depression and dependence on medication.

And, in the months leading up to June of 2010, Sherry says Lisa fell back into a dangerous, old cocaine habit.

"She was in a rut...and it was more of a stagnation where she just couldn't handle it any more," Sherry explains. She describes Lisa's behavior as "erratic... she would not be there for a couple days."

"Where was she going?" Maher asks.

"I don't know."

"Did you ask her?"

"Yes."

"What do you think she was doing?"

"I knew she was partying."

Sherry claims that is the reason why she never filed a missing persons report.

"That's what I'm trying to tell everyone out there that wants to listen now," she tells Maher. "I don't know if Lisa took off, doesn't want to be found, doesn't want help...if there truly is a problem. She's off her medication, she's doing drugs. We have a whole mix of things here."

But Lisa's Facebook friends were well aware of her troubled life.

"I gave her a pretty nice sum of money at that point and said, 'Go get your prescription meds, some food and do what you need to do..." says Tina.

They had been funneling cash to Lisa for months were and pushing her to end what they believed was a volatile and destructive relationship with Sherry.

"I took Lisa out to dinner in March of '09," Tammye says. "And as we were having dinner that night she told me that Sherry's mood had gotten increasingly angry."

If Lisa was so dedicated to Sherri, the women believe it makes no sense that at her neediest moment in life, Lisa would just take off.

"A lot of people were worried about her safety," Tina says. "But Lisa wouldn't listen - she, you know, she was a grown woman and wouldn't do anything about it"

Something else didn't make sense to the women was what they found at Lisa's house, which has been empty since Sherry moved out last summer. It was where the ladies first confronted Sherry when Lisa disappeared.

It was on that night they noticed something peculiar and which was still obvious months later when they gave "48 Hours" a tour.

"I came into this bathroom," Joni says walking with Maher. "I could peek in enough to see everything was in order and it looked very clean."

"When you look back here in the bedroom you can still see there's cat hair," notes Maher.

The ladies wondered why the bathroom was spotless. Someone cleaned the bathroom, but not the bedroom.

Was it a crime scene? And who cleaned it?

It was a mystery until neighbor Susan Scott told the Facebook detectives she noticed something odd about Sherry's hands after Lisa went missing.

"Just real red. You know like blistery, red, like if you're soaking your hands in bleach," Susan says.

When asked about her hands, Susan says, "...she said she was cleaning... and she reeked of ammonia or Clorox or whatever."

"Susan Scott says she saw you with red, raw chaffed hands and you smelling like bleach because you had been feverishly cleaning inside the house. True or false?" Maher asks Sherry.

"False," she replies. "Did not happen."

Susan Scott also says Sherry had piled up Lisa's favorite furniture outside in the weeks after Lisa disappeared. She even took a photo.

"We asked her about the furniture the neighbor said she'd been giving away... it was Lisa's furniture and the neighbor was very upset," says Tina.

Sherry says she did give the furniture away to the Salvation Army - the charity picked it up about a month after any of Lisa's friends had heard from her. Sherry says Lisa was there for the pickup, because the driver actually checked Lisa's face against her driver's license.

"They actually matched her license with her face," says Sherry.

"Lisa was standing in front of them, and they matched her driver's license picture with Lisa standing there?" Maher asks.

"Yes."

"48 Hours" checked with the Salvation Army, and according to the charity, no one from that organization ever saw or spoke with Lisa Stone at her home.

"I don't want to unjustly accuse anyone," Tammye says, "but with all of the investigating and digging...it just seems like it all points to one person..."

While the Facebook detectives have their theories, the Dallas police have a new man on the case with some ideas of his own. "You would not have to be a detective to think, 'Well something stinks here," he says.

It's been weeks since anyone has seen or heard from 51-year-old Lisa Stone, and if it weren't for the Facebook detectives, the case itself may also have disappeared.

"We were not gonna let this die, nobody deserves to just disappear," says Lisa's friend, Tammye Markle.

After being bombarded by information collected by Lisa's friends, the Dallas Police Department is finally taking the situation more seriously.

"Thousands of people disappear everyday in the United States...there's not many of 'em that have a group of friends such as Lisa had...that would push hard to find out what happened to her," says veteran Homicide Detective Jim Gallagher.

Detective Gallagher has now been assigned to the case, and says Lisa's friends have done a heck of a job keeping it alive and finds them and their information credible.

"They brought a timeline with 'em. They brought photographs with 'em. And after just a few minutes with them it was very obvious to me that we had something more than a missing person," he says.

Unfortunately, Det. Gallagher believes, at this point, the chances of finding Lisa Stone alive are slim.

"I think Lisa Stone was murdered. I think her body was disposed of," he says. "I don't think everybody surrounding this case is telling us 100 percent of the truth."

Particularly, Lisa's girlfriend. Gallagher says Sherry Henry has been less than forthcoming with information.

"She hasn't given me a clue about where Lisa is," he tells Maher. "If your roommate's missing, my first question was, 'Why didn't you make a missing person's report?'"

"And what did she say?" Maker asks.

"'I didn't think she was missing. I think she ran off.'"

Gallagher calls Sherry a person of interest. "Someone that I cannot at this point eliminate as a suspect," he says.

"Detective Gallagher got right in my face and he said, 'We think you're lying,'" Sherry tells Maher.

"What did you tell the cops when they said, 'Do you know where she is?'"

"They didn't ask me that," Sherri replies.

"They didn't ask you, 'Do you know where Lisa Stone is?'"

"They didn't ask me that!"

"No Dallas police officer has ever asked you, 'Do you know where Lisa Stone is?'"

"They didn't ask me that," Sherri says, raising her voice.

"But they're calling you today - to this day they're still calling you their No. 1 person of interest in a homicide case," Maher points out.

"They can call it a homicide case, but where's your evidence that any crime has been committed?"

"The 'no body, no crime' thing doesn't really fly anymore," Maher says. "There are a lot of murders--"

"No, what doesn't fly with me anymore is that because you lived with her you must be involved somehow - doesn't fly."

"I'm confident that Sherry isn't telling me 100 percent of the truth," says Gallagher.

That is why, just a few days after the Facebook friends dropped off the dumpster evidence, Dallas police showed up at Sherry and Lisa's house with a search warrant.

"You come in and point AK-47s or whatever automatic weapons in front of my head and chest," Sherry says of the police. "At least eight to 10 of the SWAT people around me."

"A SWAT team showed up to serve a search warrant?" Maher asks.

"You're darn right...now you tell me what was justifiable in that?"

Gallagher says it wasn't a SWAT team that served the warrant, but armed officers who were following police procedure.

He says the search produced some interesting clues.

"I have picked up some pieces of evidence in the home, pieces of clothing, pieces of trace evidence, some smears," says Gallagher.

"There are ways to find out if anything is being covered up, OK," Sherri tells Maher.

"I've watched enough crime scene shows to understand what goes on when you're

looking for evidence...I guarantee you if they had found blood spatter in that home

my butt would be in jail right now."

Sherry seems to have a lot to say about everything - and everyone else - yet she refuses to answer even the most basic question.

"When is the last time you saw Lisa?" Maher asks.

"Prior to the search warrant being issued," Sherry replies. "And that's what I'm going to say."

"So I just want to be clear so I've covered my base as a reporter," says Maher. "You will not tell us specific days as to when the last time you spoke with or saw Lisa Stone?"

"Nope, will not, no more, no more of this. It has to stop at some point. And I have to be the one to step up and say 'enough of this,'" Sherry says. "I am not here to have a bunch of people be a mystery sleuth any longer. This has taken a toll on me. What these women have done, what the Dallas Police Department have done to me, has upended my life to no end."

Interesting, because the Facebook friends say they just want their friend back, which they have come to realize may never happen.

"Do you think Lisa Stone is still alive today," Maher asks the women.

"I hope, but realistically, no," says Tina.

If something sinister did happen to Lisa Stone, two questions remain.

"What would be the motive here?" Maher asks Det. Gallagher.

"If they had severe financial problems," he replies.

"Lisa told me that Sherry would constantly ask her for money," says Tammye.

Lisa's neighbor, Juanita Burris, heard similar stories.

"You think Sherry was taking advantage of Lisa?" Maher asks.

"Oh, of course she was," Juanita replies. "She told me she ran up her credit cards. She told me she wrote hot checks on her."

"You have no proof of that whatsoever," Sherry says. "You don't see the money that comes and goes. All you know is Lisa was out of money so, 'Oh gosh, if Lisa's out of money then Sherry must have spent it.'"

It turns out that Sherry Henry does have a criminal record for stealing money. In 1995, she was convicted of forging a check for more than $8,000 - a check in Lisa's father's name.

"I don't want to get into that. I made a huge mistake, but I changed," Sherry says. "I'm a changed person.

Another possible motive: sex and love. It came as no surprise to the Facebook detectives when neighbor Susan Scott revealed that Lisa was being cheated on by Sherry.

"So Sherry had another girlfriend on the side?" Maher asks Susan.

"Yeah," she says. "She started coming over here and talking, bringing her phone and talking to this other girl."

"Weeks or months?"

"Yeah, a long time."

"Were you having a relationship with another woman?"

"The person that is in my life now is extremely important to me."

"Were you having a relationship with her in the months leading up to Lisa's disappearance?" Maker asks.

"If you're going to ask me, 'Am I having an affair?' No," Sherry says. "I have every right to move on with my life, Lisa knew this. So you tell me that Lisa didn't know this. Lisa knew."

From motive to murder, there are so many unanswered questions in this case.

"Where do you believe Lisa Stone is today?" Maher asks Sherry.

"I don't know," she replies,

"You had nothing to do with the disappearance of Lisa Stone?"

"I had nothing to do with the disappearance of Lisa Stone... Enough of this!," Sherry says emphatically. "...I want my life back... I am not guilty of anything!"

Despite their best efforts for nearly a year now, searching on foot and spending countless hours on Facebook, Lisa Stone's friends are sadly no closer to finding out what happened to her.

"There are times when we're just very disheartened and we feel so frustrated, it's like, are we wasting our time?" Tina Wiley says. "But then the next day we all get fired up again. It's like, no, we're not gonna let this die...This is not going to go into a cold case, we're determined that's not gonna happen."

Dallas Homicide Det. Jim Gallagher says they may be headed for a dead end.

"I don't know where Lisa Stone is," he tells Maher. "I have some theories."

"Buried on the property?" she asks.

"No. Into a dumpster."

Gallagher believes Lisa's body may have been put in a dumpster just like her personal belongings, which were recovered by the Facebook detectives.

"I think that's a possibility based on what that lady saw Sherry doing," he explains. "I've had many investigations where we suspected...human remains were disposed of in a dumpster. I've never recovered 'em."

"Because they usually end up going into a landfill?" Maher asks.

"I've spent weeks in landfills...hundreds of feet of garbage," Gallagher says. "It's packed, it's incinerated, it's chopped. Dogs are useless, because of the many smells."

Based on his experience, Gallagher believes the killer didn't act alone.

"Whoever did that would need some help," he says. "You would have to move that body. You would have to dispose it covertly."

If Lisa died at her home, Gallagher theorizes that whoever disposed of the body would not have be seen.

"The house is set up perfectly for something like that," he says. "There's a high fence. You could leave that property undetected and just pull out of your driveway into the alley and drive off."

Video: Scene of the crime?

Gallagher strongly believes the case will be solved.

"I can make 10 mistakes a day on this case. And probably no repercussions or I won't lose a whole lot. Whoever did this can only make one mistake, and I'm waiting for that," he says. "I need a careless whisper."

Gallagher may be waiting for a whisper, but his No. 1 person of interest is letting out a scream.

"I always told myself, 'Why aren't you out there screaming to the world that you're not guilty,'" Sherry tells Maher.

"Is this you screaming to the world you're not guilty?"

"You're darn right it is. I am not guilty of anything," Sherry replies adamantly.

"The fact is nobody has seen this woman alive since the weekend of June 2010... no one other than you claims to have seen her alive," Maher remarks. "So you understand it does not look good."

"For her Facebook friends to say that - I don't know where they're getting their information."

"It's not her Facebook friends it's the police ...it's the neighbors..." Maher says. "Did you have anything to do with the disappearance with of Lisa Stone?"

"Absolutely not," says Sherry.

Maher asks: "Did you kill Lisa Stone?"

"Absolutely not."

"Where is Lisa Stone today?"

"I don't know."

"Where do you think she is?"

"I'm not gonna speculate on that. I'm just not..." Sherry says. "Now, I may be at fault in how I handled the situation, but don't you dare come to me anymore and tell me that I haven't cooperated or I'm a murderer."

On a chilly winter morning, about a dozen of Lisa's Facebook friends gather to dedicate a bench in her memory.

"Father, Lisa should be here," Tammye prays. "Someone has taken her from us Father, and we just pray that you will help us and help the police find justice for Lisa."

Their mission will continue - in the field and on Facebook - until they can bring their friend home.

The Facebook Detectives have established an organization to show/educate others how to use the power and community of Facebook to find missing people.

Anyone with information of the case is asked to call CrimeStoppers at 1-877-373-8477