The fire service alerted officers to the fire at a home in Summerhill in Sutton Hill, Telford, at around 10.20pm on Saturday, September 19.
A man, who was inside the house when the fire broke out, was treated for minor smoke inhalation but did not require hospital treatment.
He had been rescued by fire officers from the first floor of the home using a short extension ladder.
Pc Sophia Walker, said: “The exact cause of the fire is yet to be determined but investigating officers are treating it as suspicious.
"We would like to appeal for witnesses to this incident or if anyone has information relating to it, we would ask them to please get in contact.”
Three fire crews attended the scene and used a hose to put out the blaze.
Anyone with information is asked to contact Pc Walker on 01952 214611 quoting reference 00758i of September 19, or they can report online at www.westmercia.police.uk via the Tell Us About section.
Alternatively information can be passed anonymously to Crimestoppers on 0800 555111.