A Connecticut teenager charged with fatally stabbing a classmate in their high school hallway on prom day is facing a deadline to accept a plea deal.

Eighteen-year-old Christopher Plaskon is scheduled to appear in Milford Superior Court on Monday.

That's the deadline a judge set for Plaskon to decide on the deal, which hasn't been disclosed.

Plaskon is charged with killing 16-year-old Maren Sanchez in the hallway of Jonathan Law High School in Milford in April 2014. His family and friends told police Plaskon was upset Sanchez turned down his prom invitation.

Plaskon has pleaded not guilty to murder. His attorneys have indicated they're exploring an insanity defense.

The judge previously said a trial would be scheduled if a plea agreement isn't reached by the deadline.