Denver police are investigating a series of shootings in Lower Downtown early Monday that left four people with non-life-threatening injuries.

Three women and one man were injured in the shooting that left two women still in the hospital as of 3:30 p.m. Monday and one woman and a man treated and released, said Denver police spokesman Eranda Piyasena.

No suspects have been identified or arrested.

The Labor Day shootings happened near the intersection of 19th and Market streets, said Sonny Jackson, Denver police spokesman.

An argument between two groups of people broke out around 2:45 a.m., Jackson said.

Police arrived and found two people injured in a parking lot. They were taken to a hospital, where they are in stable condition, he said.

Two other people were taken in private cars to the hospital with gunshot wounds. They had been shot at the same location, Jackson said.

“Several shots were fired. Any time you have any gunshots you have concerns,” he said. “Anyone who was there when the shootings happened is asked to contact police.”

Police impounded a white Cadillac Escalade that was pocked with bullet holes, Jackson said. Detectives have been interviewing several witnesses of the shootings, he said.

Police closed Market and Blake streets during the investigation.

Kirk Mitchell: 303-954-1206, denverpost.com/coldcases or twitter.com/kirkmitchell