A Massachusetts high school honor roll student accused of encouraging a friend to commit suicide has been charged with involuntary manslaughter.

Police and prosecutors say 18-year-old Michelle Carter, of Plainville, texted back-and-forth with Conrad Roy III in the minutes before Roy killed himself in the parking lot of a Fairhaven store. The cause of death was carbon monoxide poisoning.

Carter is a senior at King Philip Regional High School.

She was 17 at the time of Roy's death in July but has been charged as a youthful offender. That means her case is open and she could face punishment as an adult if convicted. She is free on bail.

Her lawyer tells The Standard Times that Carter did not commit a crime and expects the charge to be dismissed.