The suspect in the Monday night shootings killed five people, including one who succumbed to her injuries on Tuesday, police said.
The gunman also died on Monday after exchanging gunfire with officers in a shopping area in the Denver suburb of Lakewood.
Matt Clark, commander of the Denver Police Department's Major Crimes Division, said during a Tuesday news conference that the suspect, Lyndon James McCleod, 47, was on the radar of law enforcement and that he knew some of his victims.
Denver Police Chief Paul Pazen did not say what authorities had investigated McCleod for in the past, but noted no charges were filed.
The shootings started shortly after 5pm in central Denver along Broadway, a busy street lined with shops, bars and restaurants, where two women were killed and a man was injured, Pazen said.
A short time later, a man was fatally shot in another location, Pazen said. Gunshots were also fired along another busy street near Denver Health hospital, but no one was injured.
Later, Denver police chased the vehicle believed to have been involved in the shootings and exchanged gunfire with the person inside, but the suspect was able to get away after "disabling" the police car, Pazen said. The suspect then fled into Lakewood.
Just before 6pm, the Lakewood Police Department received a report of shots fired at a business in the city, said John Romero, a spokesman for that department.
A gunshot victim was later found and pronounced dead at the scene.
When officers found the car suspected of being involved in the Belmar shopping area, the suspect opened fire and officers shot back.
The suspect ran away and allegedly threatened someone in a business with a gun before going into a Hyatt hotel and shooting a clerk, who was taken to the hospital, Romero said. The hotel clerk's condition was not known.
The suspect also shot and wounded a Lakewood police officer after leaving the hotel, Romero said. Police and the suspect then exchanged gunfire, and the suspect died. It was not immediately clear if police officers had shot him.
The wounded officer underwent surgery on Monday night, and his condition was not immediately known.
"This one individual was responsible for this very violent crime spree that took place this evening," Pazen said.
On Tuesday, in Lakewood's Belmar shopping district, where shops line footpaths in a modern version of a downtown, plywood covered some of the windows of a wood-fired pizza restaurant where workers were cleaning up inside.
Investigators also were checking the aluminium window frame of a store for bullet holes. Nearby on the street, which was decorated with large, silver holiday ornaments, sat an older two-door Honda Civic with a bullet through the bonnet and a flat front tyre.
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