(CNN) Four Missouri police officers have been indicted by a federal grand jury in connection with the assault of a fellow officer who was working undercover.

Officers Dustin Boone, Randy Hays and Christopher Myers with St. Louis Metropolitan Police Department (SLMPD) are accused of beating the undercover officer with a riot baton and tampering with witnesses to cover up the incident, according to the Department of Justice. Myers was also charged with destroying evidence. Officer Bailey Colletta was indicted on a charge of providing false statements to a federal grand jury in connection with the incident.

The indictment also details text messages between Myers and Boone in which they talk about how much fun it will be to beat "the hell out of these s**theads once the sun goes down and no one can tell us" apart.

CNN attempted to reach the city of St. Louis, the SLMPD and associations representing the officers, but has not received a response.

In September 2017, all four officers were assigned to a Civil Disobedience Team, which conducts crowd control, in anticipation of a protest against the acquittal of Officer Jason Stockley, the US Department of Justice said in a news release.

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