A judge sentenced Jason Duane Cooper to two consecutive life terms, calling the killings "brutal and heinous."
A North County man will spend the rest of his life behind bars for the brutal stabbing death of his mother-in-law and sister-in-law.
Jason Duane Cooper stabbed his sister-in-law, 16-year-old Jenna Liebner, 56 times in her Fallbrook home in April 2006. After he killed Jenna Liebner, Cooper fatally stabbed his mother-in-law, Robyn Liebner, who ran into the family's home after hearing her daughter's screams.
The motive for the gruesome murders was never clear. There was some suggestion by the prosecution that Cooper was motivated by a possible inheritance. The defense said the slayings were prompted by an argument Copper had with Jenna Liebner over medieval literature.
Cooper had pleaded not guilty by reason of insanity, but it took the jury less than an hour to find that Cooper was sane when he killed the two victims.
At Friday’s sentencing, Cooper apologized for the murders.
"No matter how much I wish it had been my life instead of theirs, that cannot be changed," he said.
His attorney argued that Cooper should be sentenced to just one term of life in prison without parole. But the prosecutor said the murders were two separate acts, and should be punished with two consecutive terms of life without parole.
The victims' husband and father declined to read a statement in court during the sentencing. Outside court, Thomas Liebner said Cooper is a "sociopath" who would have gotten a perverse satisfaction from hearing him describe his loss, and his anger.
Thomas Liebner said he is satisfied that Cooper will spend the rest of his life in prison, mixed in with the general prison population. He said he did not want Cooper to have the "perks" that death row prisoners get.
"They get to live in a cell by themselves, they get a hot plate, they get cable TV. I mean, given they're incarcerated, it's pretty sweet. And they're protected. I don't want that for him," he said.
Liebner said it would be more of a punishment for Cooper to be with other prisoners.
"You know, if he gets sideways with those guys, you know the justice he's going to experience in there is quite different than what he got here in court," he said.