Prom day-stabbing suspect Christopher Plaskon entered a not guilty plea on Wednesday after being charged with the murder of classmate 16-year old Maren Sanchez.

The 17-year old stabbed Sanchez to death in a stairwell at Jonathan Law High School in Milford, Connecticut on April 25, and authorities are investigating whether the attack may have come after Sanchez turned him down for the prom. A witness says they saw Plaskon on top of the girl in the stairwell and tried to separate them, but was unable to get him away from her. He later tried to dispose of the bloody knife and told office staff at the school, “I did it. Just arrest me.”

Plaskon also chose to go to trial before a panel of three judges rather than a jury, but he already faces a mandatory minimum of 25 years in prison if found guilty. He could get up to 60.

Plaskon’s family released a statement, naming Sanchez’ family and saying they would mourn the loss of the teen along with the community.

“Please know that you are forever in our hearts, our thoughts and our prayers. We join with the entire Milford community to celebrate the life and mourn the loss of this most vibrant and exceptional young woman,” the statement read.

It’s not clear yet whether Plaskon will pursue a mental health defense, but his attorney, Richard Meehan, said his client is on medication.

“Obviously we have an obligation to this young man based on the things that we do know to evaluate what his mental status was. I’m a firm believer juries have a difficult time with issues pertaining to mental health in the criminal justice system,” Meehan said.

Plaskon is being held on $3 million bond and won’t see a trial until the fall.

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