Placerville — After two days of testimony, an El Dorado County Superior Court judge said he needed more time to determine whether 15-year-old Tylar Witt will be tried as an adult for the stabbing death of her mother.

Witt, 15, who has yet to enter a plea, along with her boyfriend Stephen Colver, 19, are suspected of killing 47-year-old Joanne Witt around June 11 in her El Dorado Hills home.

Judge James Wagoner said the decision that lay before him is one of the most important.

While the defense contends that Witt would have a better chance at rehabilitation if she were to stay in the juvenile court system and that she was merely a pawn in the murder plot, prosecutors say the teen was the “mastermind.”

“She was the one who wanted this to happen,” prosecutor Lizette Suder told the court.

Colver is believed to have stabbed Witt to death after Tylar Witt allegedly spiked her mother’s drink with prescription medication.

The eldest Witt’s body was discovered June 15 at her Tattinger Court home.

Colver had reportedly been living with the Witts for a few months when Tylar’s mother discovered an alleged “inappropriate relationship” between her underage daughter and the adult Colver.

Joanne Witt reportedly handed over her daughter’s journal to sheriff officials prior to her death.

The journal chronicled how Tylar Witt wanted her mother dead, perhaps killed in a violent car crash.

Judge Wagoner said Tylar Witt admitted to drugging her mother, waited for her to pass out, and then summoned Colver. Witt reportedly watched as her boyfriend stabbed her mother to death.

Colver and Witt were arrested by San Bruno Police officer on June 17 at a strip mall.

If Tylar Witt is tried as an adult and is convicted, she faces at least 25 years in prison.

Penne Usher can be reached at penne.usher@gmail.com.