Detectives investigating a fire which tore through a flat in Whalley Range are now treating it as arson.
Local residents reported being woken up by a loud bang on Mayfield Road at around 10.20pm on Sunday 20 September.
Fire crews attended the scene and worked until the early hours of the morning to assess the damage to the property.
Nobody was believed to have been in the building at the time, and no injuries have been reported.
The second and third floor windows of the property were completely blown out following the incident.
A pile of rubble could also be seen on the ground below.
Police initially said there were not thought to be any suspicious circumstances surrounding the blaze.
They now say they have reason to believe it was a deliberate and targeted attack.
No arrests have been made and and enquiries are ongoing.
Detective Inspector Chris Maddocks of GMP’s City of Manchester district, said: "Thankfully no one was injured during this incident however we now have reason to believe this was a deliberate and targeted attack.
"Our enquiries are ongoing to establish the full circumstances of this incident, and I want to take this opportunity to appeal to anyone who may have been in the area at the time.
"Did you witness the attack or see anyone in the area acting suspiciously around the time?
"Were you driving around the area and have some dash-cam footage? If you have any information that could assist us please get in contact with police.”
Anyone with information should contact police on 0161 856 6063 quoting incident number 3274 of 20/09/20. Alternatively, contact the independent charity, Crimestoppers on 0800 555 111.
