Firefighters responded to two fires in the Hermitage area of Edmonton at around 4 a.m. on Tuesday.
Three homes were significantly damaged.
One of the fires was at a condo on Hooke Road.
Edmonton Fire Rescue Services was called at 3:55 a.m. and 13 units were dispatched. The fire was declared under control at 5:51 a.m.
No injuries were reported.
On Wednesday, EFRS said the cause of the Hooke Road fire was still under investigation.
A second fire was at a home on Howson Crescent.
The son of the homeowner said that no one was living in the home at the time of the fire.
EFRS said it was called to a fire at a vacant building on Howson Crescent at 4:16 a.m. Six units were dispatched. The fire was called under control at 6:25 a.m.
No injuries were reported.
On Wednesday, EFRS said the cause of the Howson Crescent fire was determined to be deliberately set.