A block of flats in Bramhall had to be evacuated after a smoke grenade attack that set fire to a door.
Firefighters and police were called to a three-storey block on Moss Lane at the end of last month.
The grenade, described as the sort of device that would be used by paintballers, had been let off in a communal area by someone who had sneaked into the building.
It filled the block with smoke and set fire to a flat door causing around 12 people to be evacuated.
Fire crews were called at 10.45pm and put out the flames before venting the flats.
Dexter Marshall, watch manager at Cheadle fire station, said: “The whole three-storey block had to be evacuated as someone let off a high end smoke grenade.
“It was the sort paintballers would use. It scorched a door and if that had caught fire properly then it would have endangered life.
“This was more than a prank, it was malicious and very dangerous.”
Police are investigating, anyone with information can call 101 or Crimestoppers anonymously on 0800 555 111.