Officers summoned to a Brooklyn apartment discovered the grisly remains of what was once a romance: A 30-year-old man in a jealous rage had shot his former girlfriend in the head, then shot her new boyfriend in the chest before killing himself on Sunday, the police said.

The ex-boyfriend, Darnell Solomon, and his former girlfriend, Jened Duncan, 24, died at a hospital while the victim’s boyfriend, Miguel McLawrence, 33, was expected to survive, the police said.

It was the third murder-suicide in a week in New York City involving domestic violence. Two other women were stabbed to death by their abusive husbands, who then killed themselves, the police said. One of the men also killed his 5-year-old daughter, according to the police.

The violence in Brooklyn on Sunday afternoon unfolded in a second-floor apartment on a stretch of Utica Avenue in the Flatlands neighborhood, where small apartment buildings and townhouses sit near a scrap yard and a tire shop.