A former Florida police officer who fatally shot a 73-year-old retired librarian during a demonstration to the public in 2016 will not serve a prison sentence.

Then-officer Lee Coel was performing a “shoot/don’t shoot” exercise at the Punta Gorda police Department in the summer of 2016 when he shot and killed Mary Knowlton, who had volunteered to take part.

She was struck by a deadly bullet in front of about three dozen people, including Knowlton’s husband of 55 years, who were at the police Academy watching a drill about police use of firearms.

Then-police chief Tom Lewis said at the time that the revolver Coel fired had been used in previous exercises. The gun was loaded with bullets instead of blanks.

Lee Koel and K-9 Spirit.via WBBH / PGPD

Coel, who was charged the following year with the crime of involuntary manslaughter with a firearm, accepted a plea deal this week sparing him from serving a prison sentence, according to NBC affiliate WBBH. The deal calls for him to spend 10 years on probation. He faced up to 30 years in prison and a $ 10,000 fine.

He was investigated by the home office and retrained after an arrest in October 2015 during which a man was mauled by his police dog for at least two minutes. The incident was caught on dashcam video and went viral.

He was also asked to resign in 2013 from a previous job with the Miramar police Department in Florida for “failing to satisfactorily complete the Agency’s field training program.”

Mary Knowlton and her husband Gary Nonconfidentiality family

He wrote in his Punta Gorda statement that he was convicted of committing two simple violations of the policy “after he was struck by two excessive force complaints that were subsequently found to be unfounded.

The Knowlton family, a retired librarian and mother of two adult sons, received more than $ 2 million settlement approved by the Punta Gorda city Council.

Lewis, who said he held himself “100 percent responsible for the shooting, was charged with culpable negligence and found not guilty in 2017.