A 29-year-old man was formally charged Friday in the grisly slaying of a Queens family of three over the summer, police said.

Travis Blake was extradited to New York City and slapped with three counts of manslaughter in connection to the deaths of Darlene Barnett, her son, Dervon Brightly, 36, and her niece, Vashawnna Malcolm, 22, cops said.

Blake, who was visiting from Jamaica and was the estranged boyfriend of 55-year-old Barnett, is accused of fatally stabbing the three family members inside Barnett’s South Jamaica home on June 24, cops said.

Two days later, police discovered the blood scene, according to police.

Cops identified Blake as a suspect shortly after and the Regional Fugitive Task Force picked the man up in Maine on July 1, cops said.