BOSTON -- Jailhouse recordings of a Lincoln-Sudbury Regional High School teen's conversations with his parents were played during a hearing that will determine what parts of the tape jurors will hear during his murder trial.

John Odgren's lawyers claim the teen was legally insane when he allegedly fatally stabbed fellow student James Alenson, 15, to death in a school bathroom in 2007. Prosecutors said the recordings will show that Odgren was not mentally ill at the time of the attack.

During one conversation with a friend, Odgren maintains his innocence when the friend asks what he should say if people asked about Odgren.

"Well, just tell them that I didn't do it. That's the truth," Odgren said in one conversation with a friend. "I'm being persecuted for being the one who stayed behind, the one who cared enough to kneel down next to his body and try to get help even though it was too late."

Prosecutors said the teenager stabbed Alenson in the throat and abdomen before school started. Officials point to his obsession with violent novels and crime scenes.

"Did I tell you my favorite author is Stephen King?" Odgren said during another conversation.

The conversations were recorded between January 2007 and July 2007 when Odgren was 16 and at a juvenile detention center in Plymouth and include discussions with family and friends.

Throughout all of his conversations, a recording interrupts several times saying, "This call is subject to monitoring and recording."

Assistant District Attorney Dan Bennett said the recordings prove Odgren knew his conversations were not private.

Odgren's attorney Jonathan Shapiro argued that as a juvenile, Odgren cannot make a meaningful waiver of his rights and that any contact between a parent and a child should not be recorded.