The release also extended the club's condolences to the family of the victim, 18-year-old Sheldon O'Grady.
The altercation began inside the club, where two people became involved in a argument.
"Club Addiction’s security responded to a verbal argument by inviting the two people involved out of the club to ensure the safety of its customers. Security then managed to calm down the situation by talking to those people," the release said.
Security staff were forced to intervene again when crowds started to gather and another altercation started up. The staff managed to calm everyone down again, and then refused to let anyone involved back inside, the release said.
"It is only after the security staff was back at their posts that another altercation started a half a block away and that the situation worsened to reach the unfortunate outcome we now know."
Ottawa man pleads not guilty to second-degree murder
Mourad Louati, an 18-year-old Ottawa man, was charged with second-degree murder in the case. He pleaded not guilty in court Monday.
It was Gatineau's first homicide of 2013.
Louati appeared in Gatineau court and elected to be tried by judge and jury. He is being represented by Ottawa defence lawyers Joseph Addelman and Christian Deslauriers.
His next court appearance is scheduled for Feb. 5.
Suspect turned himself in
Louati turned himself in to police at 6 p.m. Sunday and he made a court appearance via telephone where the charge was officially laid.
Gatineau police spokesman J.P. Lemay said they interviewed several witnesses over the weekend before the arrest was made.
According to police, Louati and O'Grady were fighting outside the club at 117 Promenade du Portage in the city's Hull sector when O'Grady suffered multiple stab wounds. He succumbed to his injuries in hospital about seven hours later.
Friends of the victim told CBC News it was O'Grady's mother's birthday on Saturday.
Murder weapon yet to be recovered
Police have yet to recover the knife used to kill O'Grady, they said.
O'Grady had been enrolled in the Police Foundations program at Algonquin College in the fall but withdrew in October to pursue a new career path in athletics, according to the school's student support director.
He recently graduated from Immaculata High School in June 2012.
O'Grady was also a talented midfielder for the Algonquin Thunder soccer team and he was a graduate of the Nepean Hotspurs soccer program. The CBC's Stu Mills reported many teammates were asked to be pallbearers for O'Grady's funeral.
The flags are being flown at half-mast Monday at Immaculata and Algonquin. Some students were also wearing blue at the college and some high schools in honour of O'Grady.
The police investigation continues. Anyone with information about the murder weapon or about the incident should call police at 819-243-2346, ext. 6677.
An autopsy was scheduled to be performed Monday in Montreal.
Club Addiction opened as usual Saturday after the incident, according to a post on its Facebook page.