Christie was last seen on surveillance tapes during the early morning hours of Oct. 5, 2005, heading into the casino's parking lot with a man.
Where is Christie? And who was this mystery man on the casino tapes? 48 Hours correspondent Erin Moriarty reports.
From the moment Christie, then 27 years old, was reported missing, her mother, Deb Boyd, and stepfather Pat found themselves in the eye of an emotional hurricane.
"I want my daughter back, and I want her back now," Deb said.
Deputies from the Placer County Sheriff's Office, north of Sacramento, began searching a 200-square mile terrain, including backwoods and country area, around the Thunder Valley Casino where Christie was last seen.
Police got plenty of help. Pat Boyd is a cop himself in nearby San Jose, and officers from all over California rushed in to help.
The strain on Pat was enormous. Forced to sit on the sidelines while other officers investigated the case, Pat often searched on his own.
"It's the hardest thing I've had to tell my wife — we couldn't find her," he says.
Pat raised Christie from the time she was 3.
"And that's gotta be really, really tough," says Tiffany DeVries, Christie's best friend. "I think he's feeling guilty that this is what he does for a living and he can't even find his own daughter."
Christie's 29-year-old sister Stacey, a near look-alike, remains hopeful as she searched alongside her stepfather but secretly feared she wouldn't find Christie — just Christie's body.
"You want to hear details — but you don't. I get this image in my head of, 'God, what she must have been going through,'" she tearfully said.
But just a week after Christie went missing, Deb wouldn't even consider the possibility that her daughter was dead.
"She's a strong girl and very resilient, and if someone dropped her off somewhere, I hope everyone and their brother is doing everything they can to locate her," Deb said.
Christie was raised in San Jose, one of four children in a blended family. Both Deb and Pat's children come from previous marriages.
"I would say that we're an extremely sappy family but [it] definitely is full of love," says oldest sibling Debbie, who watched Christie blossom.
"She was smart. She went to college. She went out and found a great job, made good money, bought herself a BMW, was living the big life right away," says Pat.