Investigators won't say exactly why, but there was a strong sense of urgency on Thursday night. Investigators launched a search in the dark with only a few hours left in the day. At the command post there were at least 70 search and rescue volunteers preparing to and move out on foot and all-terrain vehicles.
Around 8:30 p.m. Thursday Oakland Police Department's major crimes investigative unit walked out of headquarters and went straight to Vallejo. Search crews were already combing the fairgrounds and nearby Dan Foley Park for clues leading to 50-year-old Coke who has been missing since Sunday.
Oakland Police spokesperson Ofc. Johnna Watson said they are searching "not only land, but also the body of water that's adjacent to the fairgrounds."
Police won't say who provided the information that led them to Vallejo, but they are questioning a person of interest -- Randy Alana. He is a 56-year-old man who is a registered sex offender who is in custody on an unrelated offense.
"Information during this investigation was developed that Randy Alana and Sandra Coke were seen later that evening, which would be Sunday, Aug. 4," said Watson.
That is the night Coke disappeared.
"And we know that person over 20 years ago dated Sandra Coke very briefly and that he reappeared in the Bay Area rather recently and reached out to Sandra for help," said Dan Abrahamson, a friend of the family.
Two days later, Coke's Mini Cooper was found in a parking lot not far from her North Oakland home. Two of her cellphones were also found. One in Emeryville near North Oakland, the other was tossed out near the McDonald exit ramp off I-80 in Richmond.
"We all are just desperate to see her returned home safely. So we are asking anyone with information about my sister Sandra Coke to please, please come forward," said Tanya Coke, Sandra's sister.
On Thursday the family announced a $100,000 reward for information leading to Coke's return. Coke has so many friends that apparently, it was not hard to raise the money.
The Oakland Police Department said they'll conduct the search all night long. They say they hope Coke is alive, but they say this search could determine whether or not foul play in involved.
Her friends and family suspect foul play because she has a daughter they say she would never leave behind. She left her home Sunday around 7 p.m. to go to the drugstore and she never returned.
"She left the house to go to the drugstore on her daughter's behalf and hours later, when she didn't come back, her daughter called me frightened," said Sandra's best friend Wendy Springer.
Sandra's friends believe that at some point between her home and the drugstore, she may have gotten a phone call perhaps, they say, to meet someone who apparently had information on her missing dog. The dog was stolen in May when her home was burglarized. Her family says it wasn't the first time Sandra had gotten a call from someone about her missing dog. A friend said one caller even tried to extort money from her.
On Wednesday, Oakland police went into her home to look at her computer. She had used an online dating service before.
Coke is a death penalty appeals investigator and she works for the federal defender's office in Sacramento. "We are remaining optimistic that she is being held someplace against her will but is safe and that she will be returned to us," her sister said.
Since she went missing, her family, friends and co-workers have posted fliers in her neighborhood and surrounding areas. There is even a "Find Sandra Coke" Facebook page.
Sandra's friends do not think that what she does for a living had anything to do with her disappearance. More of her friends are expected to travel to the Bay Area from the East Coast including her mother, from Ohio.
Anyone who may have seen Coke is asked to call the Oakland Police Department's missing persons unit at (510)-238-3641, Crime Stoppers of Oakland at (510)-777-8672, tip line at (510)-777-2805, toll-free tip hotline at (855)-TIPS-247, family and friends tip line at (415)-385-5190, or email tips to FindSandraCoke@gmail.com.