Mary Knowlton arrived at the Punta Gorda, Florida, police station yesterday to learn how to be a community steward.
The 73-year-old was there as a student in the citizen police academy, a two-hour course intended to give an intimate look at what makes the department in the quaint Florida town work.
On this night, the group of 35 would tour the station and talk with officers, an essential part of academy curriculum that has gained popularity across the country amid a heated national debate about police violence.
When it came time to get involved, Knowlton volunteered.
The hosting officers chose two students to role-play in a lethal force simulation, a scenario intended to demonstrate how and when officers decide to pull the trigger. Knowlton played the victim, Charlotte Sun photographer Sue Paquin told the newspaper, and a Punta Gorda police officer played a "bad guy". These scenarios are usually safe, acted out with either fake or empty weapons.
But when the officer's gun was fired, Knowlton - a mother, wife and career librarian - was hit with live ammunition.
She was rushed to a local hospital and pronounced dead.
The tragedy has rocked the historic waterfront town on Florida's west coast, home to 17,500 people and a popular destination for retirees. At a news conference, Punta Gorda Police Chief Tom Lewis called the shooting a "horrible accident" and said that everyone involved in the incident was in a "state of overwhelming shock and grief".
"Our entire police department and all of our city leaders are absolutely devastated for everyone involved in this unimaginable event," the chief said. "I am asking that if you pray, you pray for Mary's husband and family and for all of the officers and witnesses involved in this incident."
Today, city leaders issued a brief statement calling Knowlton a beloved member of the Punta Gorda community.
"We are shocked by this horrific accident and are grieving deeply over Mary's passing," the statement said. "We also would like to acknowledge the impact this had on the other participants who were present during this tragedy."
City officials are providing grief counselling to anyone who may need it.
Knowlton's Facebook page says she worked at the public library in Scott County, Minnesota, where she was from. Jake Grussing, the library director, said Knowlton worked there in the 1980s and was an active community member, serving on the library board from 1993 to 2001.
"She was a vibrant, outgoing person who was really dedicated not only to libraries, but also to serving the community," Grussing told the Washington Post.
Knowlton and her husband moved south to Florida, where she continued her librarian work and served on the Friends of the Punta Gorda Library board of directors.
Authorities have not yet said where Knowlton was shot, or why there was live ammunition in the officer's gun.
Nor have they explained how exactly the tragedy unfolded.
The officer, whose name has not been released, was placed on administrative leave, police said. The chief has asked the Florida Department of Law Enforcement to conduct an independent investigation.
Photos posted online showed the police station surrounded by yellow tape and illuminated by red and blue lights. Inside, FDLE officers questioned citizen academy students and other witnesses to the shooting, according to CBS affiliate WINK.
The citizen police academy was organised by the Chamber of Commerce, police said, but the programme mirrors the one presented as part of the city's Citizen Academy, a free, eight-week class intended to give an "up-close and personal look" at Punta Gorda government, according to the city website.
That programme includes class work, on-site visits and facility tours and is meant to "develop future leaders through well informed and civically engaged residents," according to the website.
Photos on the Punta Gorda Police Department Facebook page posted in March show academy participants engaged in simulations similar to the one that police described was taking place yesterday. Civilians are taught how to aim and holster what appears to be a fake gun or a stun gun. They climb in and out of police cruisers and ride atop department Segways.
In a series of photos, two people dressed in black protective gear and helmets appear to be simulating a physical fight. Another participant approaches the scene, gun in hand, to mitigate the situation. Here, the gun does not appear to be real. Nobody is shot.
Citizen police academies have proved to be a successful tool for law enforcement agencies hoping to improve relations between officers and the community. The first known citizen's academy held in the United States was established in Orlando in 1985, according to a report from the Criminal Justice Institute. In 2000, the Justice Department's Bureau of Justice Statistics reported that 15 per cent of police departments surveyed conducted citizen academies at the time. Seven years later, that figure had not changed.
Last year, the International Association for Chiefs of Police listed citizen police academies as an integral way to improve community relations, and establishing these courses was also named as an action item in the final report from the President's Task Force on 21st Century Policing.
There is even a National Citizens Police Academy Association, which explains the importance of the courses on its website.
"The Citizens and Police Officers meet each other face to face in a neutral, friendly setting and each becomes a person to the other," according to the website. "In the past, citizens have simply seen a uniform, now they have an understanding about the person behind the badge."
And like the one in Punta Gorda, many citizen police academies across the country teach a curriculum that includes addressing use of lethal force by police.
As citizens heard of the fatal shooting Tuesday night, they took to the comment sections of news articles online, expressing grief - and shock.
"How the hell did this happen?"