Updated

Michigan State Police tried but failed to suspend a trooper for his use of a stun gun months before he fired a Taser at a teenager who crashed an all-terrain vehicle and died, according to records obtained by The Associated Press.

Mark Bessner is charged with murder in the death of Damon Grimes, but it wasn't his only incident involving a Taser. Details are in personnel documents released to the AP through a public records request.

State police wanted to suspend Bessner for 10 days for firing his Taser twice at a handcuffed man who was running away in 2016. But an arbitrator said there was no "just cause" for discipline.

In 2014, Bessner fired his Taser at a suspect who was handcuffed. He agreed to a five-day suspension, records show, but four days were eventually dropped. It apparently was his first case of misconduct.

Bessner, 43, now faces serious legal trouble. He was charged last week with second-degree murder in the August death of Damon Grimes of Detroit, who was joyriding on an all-terrain vehicle when the trooper fired his stun gun. The 15-year-old crashed and died.

Bessner, who quit the state police after the teenager's death, has pleaded not guilty and is being held on $1 million bond. Prosecutor Kym Worthy said there was no reason for him to fire his Taser — especially from a moving patrol car.

"His behavior was criminal. We're not trying to pull the rug over anyone's eyes," a state police spokesman, Lt. Mike Shaw, said Tuesday.

Just two months earlier, an arbitrator had cleared Bessner of misconduct in how he used his Taser while chasing a crime suspect. The man was handcuffed during a traffic stop in Detroit but suddenly sprinted away and was able to clear fences.

Bessner believed the man must have slipped out of the cuffs so he used his Taser twice to subdue him. It was a wrong assumption. It's generally against state policy to use a stun gun on a handcuffed person who's in custody.

Arbitrator Steven Lett, however, found technical distinctions. He said the man was "no longer in custody" as soon as he ran away.

"The question is whether the officer's actions are objectively reasonable in light of all the facts and circumstances," Lett said, quoting a training guide from the Michigan Commission on Law Enforcement Standards.

If the 10-day suspension had been affirmed, it would have triggered an additional four days from the 2014 incident that were being held in abeyance, Shaw said.

Bessner's personnel file shows he faced a third misconduct allegation in March. State police said he was driving at high speed without emergency lights or sirens. The case apparently wasn't resolved before he quit last fall.

Bessner's file also includes praise for his work. He was recognized by the department for saving a woman who had overdosed on heroin. "Best wishes for continued success," Col. Kriste Kibbey Etue wrote in February 2017.

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Follow Ed White on Twitter at http://twitter.com/edwhiteap .