Paintings by Native American artist and activist Leonard Peltier are to be removed from an exhibition at a Washington State government building after complaints by an association of retired law enforcement officers.

The works in question were created by Leonard Peltier, a leader in the American Indian Movement (AIM) who is serving two consecutive life sentences after being convicted of killing two FBI agents on South Dakota’s Pine Ridge Indian Reservation in 1975. The shootout also resulted in the death of one Native American activist.

Peltier’s lawyer, Michael Kuzma, maintains that the prosecution withheld key evidence in Peltier’s trial, and Amnesty International says that it “remains seriously concerned about the fairness of proceedings leading to his trial and conviction.”

Law enforcement officials, however, see the case differently.

“He’s nothing but a thug,” retired FBI agent Ray Lauer tells local news outlet King5. “He’s an unrepentant cop killer.”

The exhibition marks National American Indian Heritage Month, which takes place during November, and exists in the lobby of the Department of Labor and Industries’ Tumbwater office. Four paintings by Peltier originally included in the exhibition depict Native Americans in traditional dress as well as images of wildlife.

By including the Native American activist’s work, department spokesman Tim Church says the agency didn’t intend to take a stand on Peltier’s case.

“That was in no way our intent,” Church told King5, saying that the display “doesn’t delve into any of the background of the situation that happened years ago.”