ST. LOUIS (AP) — A former St. Louis police officer has been charged with three felony counts of third-degree assault accusing him of pepper-spraying protesters and a videographer in 2017.

Charges were filed Tuesday against William Olsten. Prosecutors said the incident happened in September 2017 outside Busch Stadium during one of many protests that followed the acquittal of Jason Stockley , a white former police officer who had been accused of murder in the death of a black suspect.

Prosecutors reviewed video taken from several cellphones. According to a charging document, tempers flared after an officer used a stun gun on a protester, causing protesters to yell and curse at police.

The charging document said Olsten became visibly angry and began using pepper spray without warning, temporarily blinding three people. The document said the protesters were peaceful and were not arrested.

Two of the alleged victims who were pepper-sprayed are listed as "special victims," which could increase the potential penalties. Videographer Heather De Mian, who frequently shoots livestream video at police protests, was in a wheelchair. Rasheen Aldridge, a St. Louis Democratic committeeman, has a prosthetic leg.

Olsten's attorney, Brian Millikan, hasn't responded to an email seeking comment. A police spokeswoman said Olsten, 33, left the department in January but declined further comment.

The three alleged victims and a fourth person filed federal lawsuits last year naming Olsten and the police department.

Olsten and another officer, Joseph Schmitt, also have been charged with first-degree assault and armed criminal action over an off-duty confrontation with a patron outside a bar in 2018. That case has not yet gone to trial.

An investigation by the St. Louis Circuit Attorney's office found that the patron's gun went off when Olsten slammed him to the ground, injuring Olsten. Schmitt allegedly responded by shooting the patron, who survived.