MADISON, Wis. (AP) — Police are trying to find whoever spray-painted a message calling for justice for a black man killed by a St. Louis police officer on the Wisconsin Law Enforcement Memorial outside the state Capitol.

The state Department of Justice issued a news release Wednesday saying someone spray-painted “#Justice4AnthonySmith” on the memorial Saturday.

Jason Stockley, who is white, shot and killed Anthony Smith in 2011. A judge acquitted Stockley of first-degree murder on Friday, prompting protests.

The Wisconsin Capitol Police are investigating the graffiti. Attorney General Brad Schimel called the perpetrator a “coward” in the DOJ news release.

The memorial lists the names of 273 police officers killed in the line of duty.