A lawyer for a former Michigan state trooper is defending his decision to fire a Taser at a Detroit teenager who crashed aboard an all-terrain vehicle and died.

Trial opened Wednesday for Mark Bessner. He's charged with second-degree murder in the death of 15-year-old Damon Grimes in 2017. It's the second trial after a jury last fall couldn't reach a unanimous verdict.

Bessner shot Grimes with a Taser from a moving patrol car as he and a partner pursued the boy at high speed. Defense attorney Richard Convertino told jurors they must find Bessner not guilty if they believe the officer was trying to protect himself.

Bessner says he believed Grimes was armed , but the teen had no weapon.

Prosecutor Matthew Penney told jurors there was nothing reasonable about firing a Taser for a routine traffic offense.