RCMP officers confront the shooter at a gas station in Enfield, N.S. on Sunday. Photo by Tim Krochak/CP

The Nova Scotia mass shooting that ended with 22 people dead started with domestic violence, according to media reports.

The suspected gunman, Gabriel Wortman, 51, and his girlfriend got into a fight at a party on Saturday night in the Portapique area, Global News reported When they got home, Wortman assaulted his girlfriend and tied her up.

According to Global, the girlfriend eventually escaped and hid in the woods. Police found her alive at 7 a.m. Sunday morning. That is when they learned about Wortman being dressed as a police officer and driving a cruiser, and when the woman provided police with the image of the car.

The RCMP did not respond to a request for comment.

Earlier in the week, Nova Scotia RCMP Chief Superintendent Chris Leather said at a press conference that the police were not aware of the shooter being in a uniform until they found a “key witness.”

“Those details came in their totality to us early on the morning on Sunday after a key witness was located and interviewed,” said Leather. “The bulk of our details about our suspect came about that time.”

The RCMP have confirmed they were called to a Portapique residence at 10:26 p.m. Saturday for a firearms call. When they arrived they found “multiple casualties” but no shooter. From Saturday evening to Sunday morning, Wortman left a 150-kilometre trail of bloodshed across 16 crime scenes. The 22 dead include a teacher, nurses, a RCMP officer, and a retired firefighter. It is unknown how many of the victims Wortman knew personally.

Wortman was killed by police outside a gas station in Enfield, Sunday morning. According to the CBC, Wortman had stopped to fuel up a Mazda 3 he had stolen from one of his victims. At the gas station an RCMP crew including a K-9 unit was already there filling up an unmarked car. When Wortman went to fire on the police he was shot first, reported Global.

One of the victims is RCMP Const. Heidi Stevenson, who the RCMP said died on a highway outside Shubenacadie, Nova Scotia. Global reported that Stevenson was killed after being shot in the chest by Wortman then dragged out of the vehicle and shot again.

Wortman stole Stevenson's handgun after killing her, Global said.

During his spree, the killer reportedly used a rifle, shotgun, and a handgun. The RCMP said Wortman did not have a firearms acquisition licence, and how he obtained his weapons was a “key part of the investigation.”