DENVER -- An attorney says a Colorado Department of Corrections officer fired his gun during a weekend brawl at a Denver motorcycle show that left one dead and seven others injured.

John C. Whitfield said Sunday that the corrections officer fired in self-defense during the melee. He would not identify the officer but said he was not in police custody as of Sunday night.

Attorneys for two biker groups are blaming each other for instigating the Saturday afternoon clash. Whitfield says the officer was a member of the Iron Order Motorcycle Club, which is made up mostly of police and military.

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He would not say whether the officer fired the fatal shot.

Prisons spokeswoman Adrienne Jacobson confirmed an employee was involved in the shooting but would not identify him. He was not in police custody as of Sunday night, Whitfield said.

UPDATE: Confirming one party deceased and numerous others wounded in shooting/stabbing at Denver Coliseum — Denver Police Dept. (@DenverPolice) January 30, 2016

The melee started when members of the Iron Order Motorcycle Club, made up of predominantly law enforcement officers, were jumped by members of the Mongols Motorcycle Club, said John C. Whitfield, an attorney representing Iron Order and a member himself.

But Las Vegas attorney Stephen Stubbs, who represents the Mongols, said it was Iron Order members who instigated the alcohol-fueled brawl by taunting them into an argument that led to the deadly shooting of a Mongols member.

"None of the Mongols involved in the altercation had a gun, not even one of them," Stubbs told The Associated Press. Another club member was among the injured, he said.

"To lose a fist fight and decide that your ego can't take that, and pull out a gun and kill somebody -- that's a very cowardly and senseless act," said Stubbs to CBS Denver. "That's wrong."

Whitfield said one Iron Order member was shot, another stabbed and a third beaten.

"We don't have any issue with the Mongols," he said, adding that if an Iron Order member shot someone "it absolutely was out of self-defense."

Denver police have refused to release details about what happened or identify the clubs involved. They had made no arrests as of Sunday afternoon, spokeswoman Raquel Lopez said. Detectives were trying to identify more than one shooter.

On Sunday, police were in the process of interviewing witnesses and victims to determine who might be charged, CBS Denver reported.

"We strongly suspect there's more than one shooter," said Chief Robert White of the Denver Police Department in a news conference on Saturday. "How many firearms were recovered or how many firearms were used on the offense, that's still part of the ongoing (investigation)."

Denver Health Medical Center, where the injured were being treated, said three patients remained in critical condition and three in stable condition Sunday.

The violence put new focus on Iron Order, made up mostly of police officers and military personnel, and the Mongols, recognized by law enforcement as a highly-organized criminal gang. Members of the Mongols in Denver were charged with drug trafficking, firearms violations, witness tampering and other crimes during a nationwide racketeering investigation involving the group in 2008.

Iron Order had about 15 members in attendance, Whitfield said.

Stubbs said he believes Denver police are releasing few details because the Iron Order membership includes law enforcement officers.

Lopez said few details were being released because investigators were still trying to piece together what happened.

The Colorado Motorcycle Expo was being held at the National Western Complex and was scheduled to go through Sunday, but the city ordered organizers to cancel its Sunday events after the incident.

A statement posted on the event's website said it didn't have any information and apologized to vendors and patrons for any inconvenience.