Updated

Court testimony revealed on Wednesday that a teenager charged with killing his parents told a police dispatcher he "snapped" on the night of the stabbings.

Andrew Balcer was in court in Augusta, where officials will decide whether to try him as an adult. He's charged with double murder for stabbing Alice and Antonio Balcer to death in their Winthrop home last Halloween.

A 12-minute 911 recording played for the judge in court included Andrew Balcer saying he stabbed his mother in the back before stabbing his father when he woke up from the screams.

Eighteen-year-old Balcer, who was 17 at the time of the stabbings, also said on the recording that he did not know why he did it, and that there had not been arguments recently with his parents.

"There's no helping them," he said on the tape.

Prosecutors filed a petition to have Balcer tried as an adult, but his attorney has pushed back, saying it's not appropriate to treat Balcer as an adult. If prosecutors are successful, he could face 25 years to life in prison on each count. He also faces the possibility of no parole.

Balcer has been held at Long Creek Youth Development Center, a juvenile detention center in South Portland, since soon after he was charged. He left the courtroom in the early afternoon on Wednesday to go back to the facility and is expected to return to court on Thursday. Attorneys have said the hearing will likely take two or three days.

An interview with Balcer and detectives was also played in court on Wednesday. In it, Balcer said he remembered most of what he did, but doesn't know why he did it.

A police affidavit released earlier this year indicated Balcer told the dispatcher he stabbed his parents to death, along with a family dog. A military-style knife was found stuck in the floor near his father's body.

Balcer's parents were both 47 at the time of their deaths.