Ceiling leak (water dripping from ceiling in omakotitalo)

Kuvaus

There is a leak from the ceiling in one room of the omakotitalo I own. The roof was checked recently and did not have leaks, but somehow water manages to get into the space between the ceiling and the roof.
The house has originally a flat roof, which was covered long time ago with a metal triangular roof (standard shape), which was renovated some 15 years ago.

The leak appeared about 10 days ago, and the ceiling started to have a dark spot, as can be seen on the picture. I would need someone to take down the ceiling in this room, and find the source of the leak, and check the damage to the insulation or anything else, and put back a clean ceiling in this room.

Thank you.