Portland detectives are asking for witnesses to step forward to help solve the two suspicious fires. Firefighters arrived at the scene on the intersection of Heath Road and Tonkin Road on Thursday morning and prevented the blaze from taking hold in hot temperatures.

Less than a hectare was burnt by the fire. 

Portland’s Detective Sergeant Steve Brown said the fire was the second at the property in less than a month, leading police to suspect foul play. 

“The fact that there have been two fires within a couple of weeks make it suspicious,” Detective Sergeant Brown said. 

He said this week’s fire was at the rear of the house, while the other fire on January 5 was at the front of the house. 

“We haven’t established a cause.” 

Meanwhile, detectives are also investigating another blaze in Mount Richmond which began just after 7pm on Thursday. 

Only a small area was burnt along Telegraph Road, but firefighters and detectives are yet to find a cause.