A 50-year-old Manhattan mom was found shot to death in the bathtub of her Washington Heights apartment— and authorities are searching for her “armed and dangerous” boyfriend in connection to the slaying, police and sources said.

Cops found Ramona Rodriguez-Reynoso Friday at around 10:30 p.m., covered in blood in the bathroom tub inside her sixth-floor apartment on West 167th Street and Audobon Avenue, authorities said.

She was pronounced dead at the scene, and no arrests have been made, police said.

A stunned 36-year-old building tenant, Ines, said she heard screams “of pain and shock” from whoever discovered the body.

“You always think it’s going to happen somewhere else not near you. It’s very sad,” she added. “We were here and maybe she was asking for help and nobody listened.”

Detectives posted flyers Saturday of her boyfriend, German Reynoso, 57, naming him a “person of interest,” and warning that he should be “considered armed and dangerous.”

“It appears to be domestic,” a police source told The Post.

Cops did not say whether Rodriguez-Reynoso was shot while in the tub or whether her killer put her body there afterwards.

Community members who gathered across the street from the victim’s home were stunned by the slaying.

“This s— is shocking,” said one family friend, 40, who declined to give her name.

“I known the two of them my entire life. It’s unbelievable. It’s shocking to me. She was a good person. I saw no problems. I’ve never seen no fighting.”

A shaken next-door-neighbor, Eva Diaz, 59, said Rodriguez-Reynoso had two grown daughters, and was a devoted friend for 30 years.

“She was a very good person. She was very nice,” Diaz said.