Emergency crews responded to reports of suspicious fires overnight Wednesday, adding to a string of suspected arson cases in the past week.

Fire crews were called to a suspicious fire at a home in the 400 block of Sherbrook Street around 1:45 a.m. Thursday. Police say a mattress was set on fire at the back of the home.

Officers say the home appeared to be vacant at the time of the fire. The blaze caused about $50,000 in damages.

Firefighters were also called to a report of a tow truck on fire in the 200 block of Chalmers Avenue. Police say arson is suspected.

The incidents add to a series of suspicious fires in Winnipeg this week.

The Winnipeg Police Service is currenlty investigating 11 suspected arson cases in the first three days of May.