The officer, identified as Lee Coel, shot Mary Knowlton on Tuesday night during a "shoot/don't shoot" role-play scenario in which officers make decisions on using simulated lethal force, Punta Gorda Police Chief Tom Lewis said at a news conference.
The retired librarian was playing an officer in the scenario, which was held just outside the police complex, officials said. Coel was playing the role of a "bad guy" when he opened fire as nearly three dozen people looked on.
"I thought she was just acting at first," photographer Sue Paquin wrote. "Then thought maybe she had had a heart attack from the sound of the gunfire. But then I saw the blood."
The gun the officer used mistakenly had a live round in it, Lewis said. Knowlton was transported to a local hospital where she was pronounced dead.
State authorities are investigating the shooting. At a news conference, the police chief said he didn't want to divulge too many specifics because of the ongoing investigation. Asked how the real bullet found its way into the weapon used in the drill, he said the department was unaware there was any live ammo for the revolver. Officers thought there was only blank ammunition available, he said.
Victim wanted to show support for police
Knowlton had been speaking with her family Sunday about the negative press police had received after a series of officer-involved shootings across the nation. She decided to attend the civilian police academy to show her support for local law enforcement, said her son, Steve Knowlton.
"Our society needs them and people are human and they make mistakes, but that's why she went there," he told CNN.
The 73-year-old librarian originally hailed from Minnesota, according to CNN affiliate WINK. She was listed as being on board of directors for the Friends of the Punta Gorda Library
A longtime friend told CNN she loved children, books and learning and had myriad friends through her philanthropic work and her years with the Rosemount-Apple Valley-Eagan School District in Minnesota. She worked there for 20 years and continued part-time after her retirement, her son said.
Punta Gorda police Lt. Katie Heck said she couldn't verify how many times Knowlton was shot.
The scenario was part of a two-hour training course sponsored by the local Chamber of Commerce. While the police department has conducted five or six such sessions in the past, this was the first sponsored by the chamber, Punta Gorda police Lt. Katie Heck told CNN.
Among the program's highlights are a tour of the police department, a "show-and-tell" of various equipment used by police and the reenactment of scenarios in which officers have to make decisions on whether to fire their weapons, Heck said.
The police chief told reporters Thursday that his department had developed the role-playing exercise after seeing similar scenarios grow in popularity at agencies across the country.
"These scenarios foster conversation between citizens and police about how fast officers are required to make decisions in use of force incidents. Our department has conducted these role-play exercises over the past two years, running more than a dozen separate participants safely through the scenarios," he said. "Obviously, in this circumstance, something went terribly wrong."
Tuesday's course was attended by 35 civilians. The city called in the chaplain to counsel those participants and has arranged free counseling services for anyone else in the community who might need it.
'Just a doer'
Carolyn Hartwigsen of Edina, Minnesota, met Knowlton in the early 1980s when they were both attending graduate school at Mankato State University. The pair later returned to Mankato State for their education specialist degrees, joining forces on a thesis about the qualities of effective schools.
Though the latter degree qualified Knowlton to apply for school principal positions, she continued to work as a library media specialist, Hartwigsen said.
Reached Wednesday afternoon, Hartwigsen told CNN she was amid a walk "to clear my head of this tragedy that is filling my heart with so much pain."
Knowlton had many friends and was always smiling, Hartwigsen said. She was active in the women's philanthropic organization, P.E.O. International
, she said.
Knowlton and her husband lived in Prior Lake, Minnesota, before retiring to Punta Gorda several years ago, she said.
"She just drew you to want to be a part of whatever she was doing because you knew if she was doing it, it was worthwhile," she said.
Indeed, Lewis said he knew Knowlton personally and she was active in the community, regularly attending events in the area. She also volunteered to keep a local church's library organized, her son said.
Knowlton could make whoever she was talking to feel like they were her best friend, said Hartwigsen. She cared about everyone and her demeanor told people it was OK to open up and share their own lives, she said.
"Mary was just a doer," Hartwigsen said. "There are people who always have that positive radiance about them. You just always want to be around them."
Hartwigsen said her "heart goes out" to Coel, the officer who accidentally killed Knowlton, but at the same time she feels the Punta Gorda Police Department could have taken more precautions to make sure this sort of thing didn't happen.
Knowlton's son, Steve, said he, too, questions how something like this could happen.
"I just wish they would've done it a different way," he said. "Why did he have to shoot at her? ... No one should have a real gun pointed at them. Anything's possible. I've heard of people getting shot by blanks and being killed. So obviously there's a chance for danger there."
'Pray for Mary's husband'
Lewis described Coel, who joined the force in March 2014, as grief-stricken and said officers have been assigned to him to monitor his psychological stability. He was placed on administrative leave immediately following the shooting, the chief said.
"Officer Coel is frequently seen throughout our community providing department presentations and tours and specifically role-playing in these shoot/don't shoot scenarios as well as a police presence at youth and neighborhood events," the department said in a news release.
Steve Knowlton told CNN that he is sure Coel is "in the worst hell of his life" after the shooting, "but I want him to know that we know that I'm sure he didn't intend on this happening, and I forgive him."
Heck said she would pass the son's words along to Coel, adding that Steve Knowlton's forgiveness shows he is just gracious as his mother.
City leaders and the police department are "absolutely devastated" by Knowlton's death, Lewis said.
"If you pray, you pray for Mary's husband and family and for all of the officers and witnesses that were involved in this incident. Everyone involved is in a state of overwhelming shock and grief."
The Florida Department of Law Enforcement's investigation into the shooting could take weeks, he said.
Citizen police academies are generally encouraged as a way to bolster ties between police department and the communities they protect. A report last year from the President's Task Force on 21st-Century Policing said, "Law enforcement agencies should engage youth and communities in joint training with law enforcement, citizen academies, ride-alongs, problem solving teams, community action teams, and quality of life teams."
In the United States, 33,636 people died from firearm-related incidents in 2013, the most recent data available
from the Centers for Disease Control and Prevention.