Three St. Louis police officers were accused Thursday of beating an undercover cop during an 2017 protest and conspiring to cover it up, the Associated Press reports. The Department of Justice announced Dustin Boone, Randy Hays, Christopher Myers, and Bailey Colletta were being indicted for the beating of an officer at a September 2017 protest against the acquittal former police officer Jason Stockley—who was involved in a shooting that killed black suspect Anthony Lamar Smith. According to the DOJ, Boone, Hays, and Myers beat a “22-year police veteran” identified as “L.H.” during one night of the protests—unaware that L.H. was undercover. The three are accused of “throwing” L.H. on the ground and “kicking and striking” him with a police baton. The three—along with Colletta—allegedly conspired to “prevent information about the attack from reaching federal authorities,” including “destroying L.H’s cellphone” and lying before a grand jury. “These are serious charges and the vigorous enforcement of civil rights is essential to maintaining public trust in law enforcement,” U.S. Attorney Jeff Jensen reportedly said in a statement.