Pat Dollins/Mountain Democrat/ZUMA
08/15/2011 AT 04:00 PM EDT
Tylar Witt was 14 when she helped her boyfriend murder her mom. And on Friday she got a reduced sentence in exchange for testifying against her love-struck accomplice.
Witt, now 16, got her conviction reduced from first-degree to second-degree murder, while Steven Colver
, now 21, was sentenced to life without parole for the murder of 47-year-old Joanne Witt in 2009. Witt will now serve 15 years to life in prison.
The teens hatched the murder plot after Joanne Witt made a statutory rape complaint against Colver and gave police her daughter's diary.
During the sentencing hearing Friday in Placerville, Calif., Michael Witt – who mopped up his sister's blood from her bed after she was stabbed 20 times – unleashed his anger, calling Colver a "psychotic S.O.B."
"I hope and desire that Mr. Colver experiences the worst possible experiences our wonderful prison system can bestow upon him," Witt said, according to the Sacramento Bee
El Dorado Superior Court Judge Daniel Proud told Tylar she deprived her family of a mother "who dedicated her life to you."
"Joanne Witt loved her daughter," the judge said. "She was a protective and caring mother. She tried her best. I'm sorry Ms. Witt because the person who loved you more than anyone in the world, without reservation, is gone."
Tylar's grandfather, Norbert Witt, accused Colver in court of both murdering his daughter and of corrupting his granddaughter by exposing her to "heavy narcotics and sex."
Jan Colver vowed to appeal the decision, saying she still believes her son's story that Tylar stabbed her mother before Steven even arrived at the house.
Tylar testified at Colver's trial that they planned to commit the stabbing together, but as Colver entered the bedroom, she stayed outside and "put my hands on my ear, closed my eyes and hummed."