One woman was rushed to hospital with serious injuries after an explosive device detonated inside a Winnipeg office building Friday morning.

Police responded to reports of an explosion at Petersen King law firm on River Avenue just after 10 a.m.

According to police, 35-year-old Maria Mitousis suffered severe upper body injuries and was taken to hospital in critical condition. Mitousis is a family lawyer and has worked at Peterson King since September.

No one else was hurt in the incident.

Police cordoned off River Ave., between Mayfair Ave. and Clark St., in Winnipeg’s Osborne neighbourhood. Various forces, including a tactical police unit, a hazardous material unit and a bomb squad were called to the scene.

At a news conference Friday afternoon, Superintendent Danny Smyth said the incident is being investigated as a “specific” crime.

“We don’t consider this to be a general threat to the public or any other businesses at this time,” Smyth said.

The second law firm

Smyth said police were also called to a second law firm, Monk Goodwin LLP, located approximately one kilometre away. Smyth identified Mitousis as a former employee of Monk Goodwin, and said employees of the firm left the building as a precaution.

A bomb squad also swept the St. Mary Avenue building.

Smyth said police were still early into their investigation, and that it wasn’t clear whether Mitousis was an intended target of the explosion.

“However it came into her possession, it was an explosive device that was triggered inadvertently by this woman,” Cst. Eric Hofley told reporters at the scene earlier in the day.

There is “no indication at this point” that any other potential explosive devices are in the area, Hofley added. However, some nearby buildings have been evacuated and blocked off.

Ongoing investigation

People in nearby apartment buildings were being cautioned throughout the day to remain indoors during the police investigation.

Darien Valentine, who lives next door to Petersen King, said he felt the explosion first-hand.

“I heard a commotion. Like a big shake,” he said. “Then I'm like, what is going on? I just felt my pictures just drop down from my wall.”

Bomb squads were searching the neighbourhood for signs of other explosives during the day.

As of Friday evening, St. Mary Avenue was back open to traffic, though sections of River Avenue remained closed for investigation.

With files from CTV Winnipeg