Pat Dollins/Mountain Democrat/Zuma
06/01/2011 at 05:10 PM EDT
The brutal stabbing of Joanne Witt was not a spontaneous decision by daughter Tylar and her boyfriend Steven Colver, according to Tylar.
Testifying Wednesday against Colver in what Northern California media are calling the "forbidden love trial," Tylar described in detail the planning and motivation that went into her mother's 2009 murder
It all began after Joanne took away her then-14-year-old daughter's sexually explicit diary to build evidence in a statutory rape investigation for Colver, who was 19 at the time.
"I was in shock and then I went into a full-blown panic attack, hyperventilating, screaming, shaking," Tylar, now 16, testified, according to news reports. "Everything was in that diary. There was no way he was going to get out of the charges."
Tylar explained that the duo planned to flee town, but feared they would be caught if her mother called the police about their disappearance. The only option, they believed, was to kill her.
"I told him we could take a knife from the house. He said he would get a knife," she said.
Colver, walking up Joanne's staircase with a chef's knife taken from his restaurant job, allegedly then stabbed her at least 20 times in her sleep, while Tylar waited outside the room, unable to watch.
"I couldn't do it. I couldn't go inside," she said. "I put my hands over my ears, closed my eyes, and hummed."
Tylar previously pleaded guilty to first-degree murder and agreed to testify against Colver. She faces 15 years to life in prison.