PUNTA GORDA, Fla. — The family of an Austin native shot and killed when a police “shoot/don’t shoot” demonstration in Florida went shockingly awry has spoken out, and her son says he’s forgiving the officer who fired the fatal shot.

An officer shot and killed Mary Knowlton, a 73-year-old former librarian, with what police said was real ammunition used by mistake at an event designed to bring police and the public together.

Mary, a well-known community volunteer, was shot after being randomly selected to take part in the role-playing scenario illustrating the split-second decisions an officer must make about firing. It was part of a popular citizens academy attended by 35 people, including her 75-year-old husband, and the police chief.

Her son, Steve Knowlton, said his father was “devastated.”

Steve said in an interview Wednesday at his parents’ home that, on his mother’s behalf, he was forgiving the officer who fired.

“There’s too much hate in this world, in America, we always feel like we need revenge and it doesn’t solve anything,” he said. “I obviously can’t say it’s easy to forgive, but it needs to be done. She’s watching me now.”

Mary attended the class with her husband and it was supposed to be “a fun night,” her son said.

Steve tearfully told reporters Wednesday that he used to tease his mother about how much she worked in retirement. She helped with the local Chamber of Commerce, was active in a program for at-risk kids, loved the library and spent hours there volunteering.

Mary moved to Florida after living for years in the Twin Cities area of Minnesota. Her Facebook said she had been a librarian at Scott County Public Library in Savage, Minnesota. She studied library science at Minnesota State University in Mankato, Minnesota, and elementary education at George Mason University in Virginia. The profile information said she’s from Austin, Minnesota, and is an AHS graduate.

Books and magazines lay scattered on tables of the home she shared in Florida with Gary, her husband of 55 years. The couple split their time between Minnesota and the small Gulf Coast community. She had two sons.

Steve said that his father hadn’t yet been able to see his wife’s body, more than 12 hours after the shooting.

“To see your wife shot and killed, and not be able to see her …” Steve Knowlton said, his eyes filling with tears.

And yet, Knowlton said his mother would have wanted him to forgive the officer who pulled the trigger.

“I forgive him. My mom was very spiritual. She brought us up right,” he said.

Carolyn Hartwigsen, of Edina, Minnesota, told The Associated Press she was a longtime friend of Knowlton, adding she loved books and sought to instill that in young readers.

“So much is on the internet now. But, books are so important to have in children’s hands. That was important to her,” Hartwigsen said.

Hartwigsen said Mary and her husband would come back to Minnesota periodically to visit.

“She was the salt of the earth, a beautiful soul and the kindest woman you would know,” she said.

‘It just breaks my heart’

Authorities didn’t immediately say how a gun with a live round came to be used at Tuesday evening’s demonstration, noting blank rounds are typically used in such classes. The officer has been placed on administrative leave, and the Florida Department of Law Enforcement is investigating.

Punta Gorda Police Lt. Katie Heck identified the officer involved as Lee Coel, 28. He’s been placed on administrative leave.

Heck said Coel has worked for the department since 2014. She said Coel frequently gave department presentations and tours, “specifically role-playing in these shoot/don’t shoot scenarios.”

The class put on by the Chamber of Commerce and the Punta Gorda police station, was just one stop during the weeks-long curriculum.

Officer Oscar Vasquez of the Jacksonville, Illinois, Police Department, who is president of the National Citizens Police Academy Association, said he had never heard of anyone taking part in such courses being fatally shot. He said most departments do not use weapons in “shoot/don’t shoot” scenarios that are capable of firing a live round.

“When we run scenarios, we will use starter pistols,” Vasquez told The Associated Press. “You can’t even put live ammunition in them.”

Some departments use video simulators or other non-lethal devices, he said. Officers involved in most citizen academies don’t typically even bring service weapons into classes, he added. Citizens are told beforehand that live weapons won’t be used.

“We put them in the shoes of the officers so they can see, real time, the decisions we have to make and the time frame we have to make them.”

With suspicions running high between police and many citizens in recent years, particularly in minority communities, Vasquez said, a death like the one in Punta Gorda is extremely unfortunate.

“It just breaks my heart. It’s such a tragedy,” he said.