LAKEWOOD, Colo. (AP) — An officer was killed and three others were wounded during a firefight in a Denver suburb Thursday evening with a man who was fatally shot by police, according to law enforcement.

The Lakewood officers had responded to a call about a suspicious person attempting to get on a public bus, police spokesperson John Romero said during a news conference. The person may have been involved in a hit and run earlier that day, he said.

When police arrived at the bus around 6:30 p.m., the man opened fire, Romero said. It wasn’t clear whether the shooting happened on the bus or near it.

The three officers are being treated at the hospital and their condition has not been released.

Another person was also injured, although it was not immediately clear what caused their injury, Romero said.

Lakewood Police are investigating the shooting and asked the public to avoid the area.

The names of the officers and the suspect have not been released.

The Regional Transportation District said it is deeply concerned by the shooting and that it is fully cooperating with police as they conducts their investigation.

Colorado State Patrol said in a statement that their hearts are broken over the death of the officer.

“To the three additional Lakewood Agents who were injured in tonight’s shooting, we are sending our deepest prayers, strength and best wishes for a full recovery,” the statement said.