Gore didn’t tell his supervisor about the incident or write a police report, Belmar said.

The department first learned about the incident when Wilson called four days later seeking to have his medical bills paid, Belmar said. Detectives investigated the allegations and turned their findings over to the prosecutor’s office on May 6.

Gore was put on paid leave while authorities investigated, Belmar said. Friday, he was suspended without pay.

“This alleged unprovoked use of force outside the bounds of department policy and without cause cannot be tolerated,” the chief said.

Second-degree assault is a felony in Missouri, punishable by up to seven years in prison and a $5,000 fine.

Video surveillance and information from witnesses helped make the case against Gore, authorities say. Authorities said they won’t release the video to reporters because it is evidence in the case. The video showed Gore and Wilson on the platform, but the alleged attack took place out of the view of the camera, authorities say.

Neither Wilson nor Gore could be reached for comment. Court records did not yet list an attorney for Gore.