A 55-year-old man and a 59-year-old woman – believed to be siblings – were both found shot in the head when cops responded just before 8 a.m. to a 911 call for multiple shots fired inside a co-op building on Johnson Avenue in Spuyten Duyvil, authorities and sources said.

An 86-year-old woman – who sources say is believed to be their mother – was discovered with a gunshot wound to the face, cops said.

The younger woman, who was discovered lying in bed, was pronounced dead at the scene, cops and sources said.

The elderly victim was rushed to Harlem Hospital in critical but stable condition, police said.

Meanwhile, the man – who was discovered lying in the hallway with two guns on his lap – was also declared dead by EMS, cops said.

Investigators believe the man fired at his relatives and turned the weapon on himself, the sources said.

None of the victims were immediately identified by police, and the investigation is ongoing.