A photo from the scene of a shooting in Olde Town Arvada. (Ryan Dunn, Colorado Community Media)

DENVER — A police officer involved in a shooting that killed three people in a Denver suburb has been put on administrative leave, suggesting that the officer may have shot one of the people who died.

Killed in Monday’s shooting in Arvada were a fellow officer, a man police have described as a suspect and a bystander who intervened and has been credited with preventing more bloodshed. Police have not said who shot the bystander or the suspect.

Officers are typically placed on leave after shooting people until an investigation can determine if the shooting was justified or whether the officers should be criminally prosecuted.

Arvada police spokesperson Detective David Snelling confirmed Thursday that an officer has been placed on leave but said he could not discuss the officer’s actions to avoid interfering with an outside investigation being conducted by a team of area law enforcement agencies led by the district attorney’s office. A spokesperson for the First Judicial District Attorney’s Office did not immediately return a call regarding the investigation.

According to its policy, the team investigates officers’ use of deadly force, typically shootings, but it can also be asked to investigate the deaths of people in custody or injuries caused by police.