An off-duty police officer, enraged at finding her girlfriend and another woman in bed together, shot them both Wednesday — killing the new woman in the relationship and wounding the girlfriend, police sources said.

The officer, Yvonne Wu, 31, who is assigned to the 72nd Precinct in Brooklyn, opened fire on the lovers in a home at 19th Avenue near 80th Street in Bensonhurst just after 5 p.m., hitting both women in the chest, police sources said.

The officer’s girlfriend, 23, suffered a non-life-threatening wound; the other woman, 25, was critically injured and died of her injuries, sources said.

When one of the victims called 911, the operator could hear someone in the background saying, “That’s what you get,” sources tell the New York Daily News. The 911 caller identified herself as Jenny Li, the sources said.

Medics took both shooting victims, as well as a third patient, possibly the off-duty officer, to Maimonides Hospital.

The off-duty cop was in custody, police sources said.

Theresa DiGirolamo, who lives up the block, said she heard what sounded like a paper bag popping, then saw one of the victims taken away by ambulance.

“It’s like a pop, pop, one, two, three. Then four and maybe five,” she said.

DiGirolamo said she walked to the corner, and saw medics loading one of the women into an ambulance, “her face like gray, like no life, lifeless.”

“This is a very quiet neighborhood. This is shocking for everybody,” she added. (New York Daily News)