MIAMI (AFP) - A 73-year-old Florida woman suffered a fatal gunshot wound while role-playing in a police simulation designed to teach people how officers decide when to use lethal force.

Mary Knowlton, a librarian, died on Tuesday (Aug 9) evening after the accident in Punta Gorda on Florida's west coast, the police department said.

She was one of 35 people taking part in a two-hour course given by the so-called Citizen Police Academy.

Knowlton was one of two people selected randomly to role-play in a scenario in which they had to decide whether to use lethal force against a "bad guy" played by a police officer.

But the officer's gun turned out to have live ammunition, and discharged.

Knowlton was rushed to a hospital but died.

"I absolutely am devastated for everyone involved in this unimaginable event," police chief Tom Lewis said at a press conference.

The officer involved in the shooting has been placed on administrative leave pending an investigation.