In newly released tapes, Vicki Robinson's daughter's and two friends' stories vary on who did what that night.
The teens in the stolen minivan made it halfway across the country before they were stopped cold in a dusty Texas town by a sheriff in a tall, white cowboy hat.
Separated inside small-town jails, Valessa Robinson, her boyfriend Adam Davis and their friend Jon Whispel began to tell detectives three very different tales of the horror they had left behind in Tampa.
Valessa, then 15, told detectives in a dull voice that she was on LSD that night in June 1998 when she attacked her mother, Vicki Robinson, in the kitchen of their Carroll-wood home, pinned her down, and brandished the footlong knife while the boys were in the bedroom.
"I remember I had stabbed her in her throat and it released a lot of blood," Valessa told detectives. "And she wasn't dead yet, and so I stabbed her again twice in her back."
Her confession came in one of several audiotapes and videotapes released Monday in the first-degree murder case against Valessa and Davis, 20, a couple police say vowed to stay together no matter what. Their friend Whispel, also 20, who recently agreed to testify against his friends, pleaded guilty to a reduced charge of second-degree murder and has already been sentenced to 25 years in prison.
In her short interview with Tampa detectives who flew to Texas when the teens were caught in Pecos County in July 1998, Valessa attempted to shoulder the blame.
But it was only one version of what happened to Mrs. Robinson, a bubbly, deeply religious single mom who worked as a real estate agent and had been struggling to control a troubled and defiant daughter.
Mrs. Robinson's body, still clad in her peach nightgown and crucifix, was stuffed into a plastic garbage can and left hidden in the woods before the captured teens drew maps to the body for police.
In his statement to detectives, Davis, a drifter with a criminal record, implicated all three. He said the idea brewed that night at a local Denny's while they were tripping on acid and trying to figure out a way to stay together.
He said Mrs. Robinson was trying to break up his relationship with Valessa and gave a matter-of-fact solution: "So we wanted to inject her with heroin and put her to sleep," he said. When they couldn't find any heroin, they settled for a syringe, he said, and headed back to the Robinson home where Mrs. Robinson was already in bed, he said.
"We filled the needle up with bleach and an air bubble, thinking that might help," Davis told detectives. After Mrs. Robinson woke up, upset that the boys had not gone home yet, Davis attacked her in the kitchen and put her in a choke hold until she was unconscious, he said.
He said he tried to inject her in the neck while Valessa pinned her mother's legs down.
"And I started raging because I was tripping so hard," Davis said. "And Jon brought out the knife. . . . He said "Here, use this.' "
"And I don't know how I did it. I don't even know what was going through my mind when I did it, but I just sliced," Davis said.
Whispel's account to detectives was similar to what he recently told prosecutors as part of his plea deal, except for one major detail: In Texas, he didn't admit that he handed Davis a knife. In his original statement, Whispel said he was in Valessa's bedroom when Mrs. Robinson was killed.
Whispel and Davis both described an elaborate cleanup: laying a trail of towels and garbage bags to catch the blood, swabbing the kitchen tile, putting the body into a garbage can, taking the back seats out of Mrs. Robinson's minivan so the can would fit inside.
The men said they intended to dig a grave in a remote area but gave up when the ground was too hard.
There also were plans to load the trash can down with concrete and toss it into a creek, but in the end they simply hid it under some dead palm fronds, Davis said.
Davis' attorney Rick Terrana said he will challenge the admissibility of the confession before Davis' trial, scheduled for Nov. 1. The attorney for Valessa could not be reached for comment late Monday, but similar motions are expected on her behalf before her Dec. 13 trial.
"I remember I had stabbed her in her throat. . . . And she wasn't dead yet, and so I stabbed her again twice in her back."
Adam Davis: "And I started raging because I was tripping so hard. And Jon brought out the knife. . . . He said, "Here, use this.' "
"I remember I was sitting in Denny's with Adam and Valessa and I heard something about killing mother."