Updated

Three people, including a Colorado police officer,  a "Samaritan" and a suspect, were killed Monday in a shooting in a shopping district just outside of Denver, authorities said.

The Arvada Police Department said an officer was down following a shooting in the city's Olde Town district just around 1:30 p.m. Arvada Dep. Chief Ed Brady said a veteran officer initially responded to a call about a "suspicious incident" near a library. 

Minutes later, 911 calls were made about possible shots fired and an officer being struck by gunfire, he told reporters during a news conference. Another person, possibly a bystander, was fatally shot by a gunman, who was also killed, Brady said. 

Authorities have not released the identification of anyone involved in the deadly shooting. 

A CodeRED was issued shorting after the shooting telling people in the area to shelter in place and call 911 if they see suspicious activity, Fox affiliate KDVR-TV reported.

Fox News has reached out to the Arvada Police Department but has not heard back. Brady said there was no ongoing search in the area and investigators don't believe there are any other suspects. 

Residents in the area were evacuated as authorities searched for possible explosives, which is standard protocol, the outlet reported. Nearby businesses were also asked to close early. 

A bomb squad unit was outside a home Monday evening but it was not clear if it was related to the shooting hours earlier. 

Arvada Mayor Marc Williams described the unidentified officer as a "highly respected" officer whose "involvement in the community went far beyond just his police duties."

"You've got an officer with a family who went to work this morning thinking he was going to do his public service and he didn't come home," Williams told Fox News. "I'm just so sad for his family and sad for our community that now we're part of the statistic of these horrible losses."

The city has lost two officers while in the line of duty prior to Monday, but never to gun violence, Williams said. 

The Arvada Police Department said an officer was down following a shooting in the city's Olde Town district just around 1:30 p.m. Arvada Dep. Chief Ed Brady said a veteran officer initially responded to a call about a "suspicious incident" near a library. ( )

In a show of support, crowds lined to streets during a procession for the fallen officer.

The Arvada Police Department honored one of their own Monday with a procession after he was killed while responding to a call hours earlier. 

Gov. Jared Polis, a Democrat, said he was thinking of the officer's family. 

"My thoughts are with the family and friends of the officer who was tragically killed in the line of duty while swiftly and bravely responding to protect civilians in the area," he said in a statement. 

Olde Town is the city's downtown district and home to various shops, galleries and restaurants, according to the city's website. It’s listed on the National Register of Historic Places.

A procession for a fallen Arvada, Colo., police officer.

A woman who lives nearby where the shooting occurred told the news station she heard three gunshots and saw police vehicles and ambulances respond. 

Brady Turner said he was pulling into the Army and Navy store in the area when he noticed police cars driving in behind him and a person on a stretcher being put into an ambulance in between the parking lot and the store. Turner said he took off in his car.

An Arvada, Colo., police officer was injured Monday and a suspect was shot, according to local reports. (NewsNation )

"I just got out of there," the Arvada resident said.

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The city tweeted that City Hall was closed for the remainder of the day and Monday night's City Council meeting had been canceled. The shooting briefly forced a shutdown of a light rail station in the downtown area. 

The Associated Press contributed to this report.