A Calaveras County judge has declared 14-year-old Isiah Fowler responsible for the death of his sister, Leila.
Leila Fowler was found stabbed to death in the family's Valley Springs home in 2013. Isiah Fowler was arrested just over two weeks after Leila was killed.
Fowler's family stormed out of court Tuesday, outraged.
The Fowlers told the media they are disappointed in the county because they believe the killer is still out there.
"It was a random act ... this case was handled so poorly, we never know what happened.... [prosecutors] in no way showed certainty either way. Hopefully, no one else's daughter has to die," Isiah's father Barney told FOX40 Tuesday.
Calaveras County prosecutors said Monday during closing arguments that there was no evidence of an intruder in the house and that the alleged murder weapon was cleaned, yet small traces of Leila's blood were found ingrained within the handle.
Since Isiah was only 12 when his sister was killed, he was charged as a juvenile. That means, there was no jury sitting on his case, only a judge who came to a verdict in just a few minutes Tuesday.
The judge told the court he was hard-pressed to believe Isiah's story, that an intruder had broken in and stabbed Leila 22 times in a matter of 20 seconds.
Isiah will be sentenced next month. He could be behind bars until he is 23.
His defense attorneys are already planning an appeal.
Stay with FOX40 and FOX40.com for the latest information on this developing story.