A dispute that flared outside Auraria Student Lofts on 14th Street ended with two men in critical condition early Sunday after one of them opened fire on a crowd and a Denver police officer and a security guard returned fire.

The incident began outside the student housing shortly after 1 a.m., when two groups began to scuffle and a guard at the apartment complex sprayed a chemical agent at them to break them up, said Ron Saunier, commander of the major crimes and investigations unit.

The guard than used a flashlight to signal two off-duty Denver police officers who were working at the nearby Epernay Lounge.

The guard identified the members of one of the groups to police, Saunier said.

Two men from the second group began “walking back to the scene, and one of them started firing.”

An officer told the suspect to drop the weapon, Saunier said, and when he didn’t, one of the cops and the guard fired on him. Multiple rounds were fired during the incident, Saunier said.

Bars were letting out at the time, and there were a number of people in the area. No bystanders were hurt.

Police don’t believe any students were involved, and Saunier said there is no indication the incident was gang-related.

Police believe the two wounded men, whose identities they haven’t released, are brothers. One of them is 40 years old, and the second is 35, Saunier said. “They are definitely older than what we see in gang involvement.”

Police haven’t identified the two, who are expected to survive.

The 40-year-old was armed with a semi-automatic handgun. Saunier said he expects that man to be charged with aggravated assault and possibly attempted murder.

His brother, who was unarmed, probably will not be charged, Saunier said.

Later, police contacted two other people who had been at the scene, and they were interviewed as witnesses.

Saunier said he doesn’t expect any more arrests.