Investigators are looking into the cause of a fire that leveled a building in downtown Winnipeg Tuesday.

The fire was reported in the 200 block of Logan Avenue, near Main Street, around 3 a.m.

When firefighters arrived, the 100-year-old building was fully engulfed by flames.

"There must have been a lot of flames earlier because by the time we got here, the building had already collapsed," said Maj. Brian Slous from the Salvation Army.

Firefighters succeeded in saving neighbouring buildings, which only sustained minor smoke and water damage.

"It is actually a very dangerous environment for firefighters because once the beams start to go the building will collapse and…the only walls remaining are the ones supported by the adjacent building," said Ken Sim, deputy chief with the Winnipeg Fire Paramedic Service.

The warehouse building belonged to Mitchell Fabrics. One of its owners tells CTV News it's been a difficult day because plans were in the works to revitalize the building, before the fire destroyed it.

One person living in a condo next door to the building was taken to hospital as a precaution and was later released from hospital.

People in the area are fearful an arsonist could be to blame for the fire, especially coming on the heels of two fires in Point Douglas.

While arson hasn't been ruled out in any of the three fires, officials said there are still investigating the causes.

Anyone with information on the Logan Avenue fire is asked to contact police at 986-6813, or Crime Stoppers at 786-8477.

A Winnipeg Regional Health Authority building near the fire site on Logan and Main wasn't damaged, but will remain closed until Oct. 31, said officials. Smoke got into the building through its heating and ventilation system and will take time to clean out. The primary care clinic has been relocated to 425 Elgin Avenue. Staff members are currently notifying patients of the changes.

Crews were also kept busy with another fire in Winnipeg early Tuesday, with a blaze reported at a house in the 300 block of Agnes Street. No injuries were reported. Investigators are looking into whether that blaze was caused by a firebombing and if it is gang related.

Anyone with information on that fire is asked to contact investigators at 986-6219, or Crime Stoppers at 786-8477.

- with a report from CTV's Caroline Barghout