About 30 people were released from police custody Sunday after being questioned about the shooting.
The female officer was shot in the leg while breaking up a disturbance involving nearly 20 people at a bush party. It was held in a wooded area along the Gatineau River, close to 1885 Saint-Louis St., near d'Auvergne Street.
Witnesses of the disturbance called police at about 10 p.m. ET, saying that at least one person was carrying a firearm.
Police arrived at the scene about 12 minutes later and shortly afterward a female officer was shot in the right leg.
The injuries weren't life-threatening and the officer, who has three years on the force, underwent minor surgery later Sunday morning.
"She's in pretty good condition … her family is surrounding her, police officers and people from the hospital, so she's in pretty good condition," said police spokesman Const. Pierre Lanthier on Sunday.
Lanthier said Monday that officers are now looking into whether she shot herself.
"We wil talk to the female officer who was involved in the shooting, we will meet some people again today to try to get a better idea of what happened," he said.
"If it's an accidental gunshot, we will confirm that."
Man arrested for unrelated matter
Police cordoned off a large area between Picardie Street and Gatineau Avenue, and about 30 people were taken into custody for questioning about the shooting.
Gatineau police called Quebec provincial police for help to comb the area early Sunday morning. A helicopter was dispatched and began aerial sweeps at about 4:30 a.m. Sunday.
As the helicopter flew overhead, a Gatineau police officer monitoring the perimeter saw a man trying to leave.
The 20-year-old man was arrested at about 5:30 a.m.
Of everyone taken into custody, he's the only one that hasn't been released. He was wanted on an outstanding, unrelated matter, and will appear in court on Monday, police said.
The helicopter resumed aerial sweeps from 6 a.m. to 9:45 a.m., at which point Saint-Louis Street was reopened to the public.