Boston- A 21-year-old woman allegedly stabbed her boyfriend in the back with a kitchen knife last night in Jamaica Plain after catching him looking at porn, according to police.

Claribel Peralta is scheduled to be arraigned Monday in West Roxbury District Court on charges that she plunged a knife into her 33-year-old boyfriend and pulled out clumps of his hair, police said.

“Initially she told officers that she was in the bathroom and walked out and saw him stabbed,” said officer Eddy Chrispin, a Boston Police spokesman.

A man in an elevator at the public housing complex at 125 Amory St. reported hearing “loud banging and screaming.”

Police arrived at about 3 p.m. to find the victim lying on the ground near the elevator and a blood trail leading down the hallway to the doorknob of an apartment.

A witness in the third-floor apartment where the melee began said the woman became enraged after finding the victim with pornography. The witness told police the woman washed the knife in the bathroom and set it on the kitchen table before walking out of the apartment, police said.

The victim was in stable condition at Beth Israel Deaconess Medical Center last night.