Two people are dead and a third person is injured after what appears to be a violent family altercation in Brighton Beach.

According to police, 30-year-old Kostyantyn Proskurnyak stabbed 59-year-old Voclodymyr Yeushchenko inside a first-floor apartment at 1070 Oceanview Ave. at around 2:30 a.m. Yeushchenko was pronounced dead at the scene.

Though police won't give too many details, published reports say the victim was the stepfather of Proskurnyak.

Police say it appears Proskurnyak then jumped from the building, committing suicide. Police say when they were called to the scene, he was discovered outside the building with severe body trauma. He was pronounced dead at Coney Island Hospital.

Officers say a 29-year-old woman, believed to be Proskurnyak's sister, was also in the apartment at the time and tried to intervene. She was later found just a few blocks away at Brighton Beach and Coney Island avenues with stab wounds to her back, wrist and forehead. She's listed in stable condition at Lutheran Medical Center and is expected to be OK.

It is unclear what sparked the altercation. The investigation is ongoing.