Edgar Bonilla, 41, was arrested Monday after a confrontation at an assisted living facility in southwest Philadelphia, the Philadelphia Daily News reported Wednesday.
Bonilla went to the facility to visit a 39-year-old woman but ended up confronting the victim, whose name and age were not reported.
Police said Bonilla allegedly pulled out a butterfly knife, stabbed the victim multiple times in the chest, then cut off his testicles.
"[Bonilla] doesn't like the way the conversation goes between the young lady who lives on the second floor, who is also disabled, [and the victim]," said Lt. John Walker, of Southwest Detectives.
The victim was taken to the Hospital of the University of Pennsylvania where he was listed in critical condition, the newspaper reported.
Bonilla faces charges of attempted murder, aggravated assault, possession of an instrument of crime, robbery, burglary and theft. He was being held with bail set at $5 million bail.