US police charged with beating undercover officer during protest

Demonstrators protest outside the St Louis city jail in September 2017 (AFP Photo/SCOTT OLSON) (GETTY IMAGES NORTH AMERICA/AFP/File)

Chicago (AFP) - Several police officers in the US city of St Louis were charged Thursday with illegally beating an undercover officer posing as a protester and then attempting to cover up their actions.

The charges stem from a widely-criticized police response to September 2017 street protests in the Midwestern city during which police were accused of using excessive force.

Federal authorities are investigating the way police handled the protest.

Officers Dustin Boone, Randy Hays and Christopher Myers are accused of knocking to the ground an undercover officer who was monitoring protesters, and then kicking and striking the officer with a police baton.

A fourth officer, Bailey Colletta, was accused of lying to a federal grand jury during its investigation of the incident.

The undercover officer, who was not named, was described as a 22-year veteran of the St Louis police force.

The protest had been against the acquittal of former officer Jason Stockley in the fatal shooting of Anthony Lamar Smith.

That case, involving a white officer and a black victim, was one of many around the country that inspired public demonstrations, policing reforms, and led to the Black Lives Matter movement.

The four indicted officers were suspended without pay, according to the city.

"In a few instances, some officers have fallen short of the professionalism required to work in our Police Department," St Louis Public Safety Director Jimmie Edwards said in a statement.

"I believe (the four) officers... are outliers and that the charges levied against them are isolated and not indicative of our Police Department."

But the American Civil Liberties Union said the indictment revealed a culture of unconstitutional behavior in the St Louis police force.

"While these officers have been indicted for illegally abusing an undercover officer," said the ACLU's Tony Rothert, "there has still been no real accountability for... officers who engaged in the same behavior toward protestors."

The four officers face various felony charges, including deprivation of constitutional rights and obstruction of justice.