A Michigan teen is accused of violently stabbing a classmate to death and then laughing about it, the Detroit Free Press reports.

Prosecutors on Friday charged 17-year-old Tanaya Lewis with first-degree premeditated murder in connection with the fatal stabbing of 16-year-old Danyna Gibson.

The suspected motivation for the attack: an argument over a boy.

Court documents obtained say Lewis came up to Gibson at their high school on Wednesday with a straight-edged kitchen knife. She stabbed the girl at least twice initially, including once in the heart.

Lewis reportedly then chased the girl around a classroom and stabbed her again, this time a hammer-fist in her back, puncturing her lung.

A teacher intervened and pushed Lewis away from Gibson, but Lewis attempted to get past the teacher, yelling, “I’m going to kill her.”

Witnesses reportedly say they saw Lewis laugh and smile during the encounter.

Police are investigating whether Lewis posted threats against Gibson on social media before the attack.

Gibson was a straight-A student and was involved in numerous school activities, including marching band and color guard.

Lewis was reportedly angry because she believed Gibson had told Lewis’ boyfriend that Lewis was cheating on him, according to Police Commissioner William Dwyer.

Dwyer declined to comment as to whether that was true, but he said police had obtained text messages between Lewis and her boyfriend, and said the pair had driven to school together Wednesday morning to reconcile.

Authorities have detained Lewis and she remains in jail without bond. She is expected to return to court this month.

The incident happened at Fitzgerald High School in Warren, Michigan, which is in metropolitan Detroit.

Friends of the victim posted a memorial video on Facebook.