The 17-year-old Milford boy accused of stabbing a classmate to death on the day of their prom appeared in court Tuesday.
Lawyers for Christopher Plaskon say they will use a defense of mental disease or defect also known as an insanity plea.
Plaskon is charged with murdering Maren Sanchez, 16, in a hallway at Jonathan Law High School last April.
Police were looking into whether the attack was related to Sanchez's refusal to be Plaskon's prom date.
The state's attorney also filed a motion saying they want Plaskon examined by their own doctors during the short hearing.
After that, Plaskon's attorney says the case will go to trial by a three-judge panel instead of a jury.
He says because of the nature of the case and their new defense, it should be better for his client.
Plaskon is due back in court in July, but no specific date has been set.