Police were called to a house in Delta Walk, Moston, at 10.20pm on Sunday.
Officers discovered the body of a 41-year-old man who had been stabbed.
A 13-year-old girl suffered serious injuries, also believed to be stab wounds, and was taken to hospital where she is in a critical condition.
Just before 1am, police were called to Watfield Walk in Harpurhey after a man threatened a car owner with a knife and stole a vehicle.
A short time later, the vehicle was seen by police near Rochdale Road. When officers approached, a 34-year-old man drove the car into the side of the Alliance pub.
He was taken to hospital suffering from a stab wound and injuries consistent with a collision but died a short time later.
No one else was injured in the smash.
More top news
A four-year-old boy is among 20 people to have died in some of the worst flooding West Virginia has seen.
The heavy showers will ease off this weekend.
Labour MPs are attempting to build a consensus for a single challenger to Corbyn, while the big game in the Tory Party is Stop Boris.