The suspect had connections with the clothing business and possibly once had a clothing store, officials said. He reportedly carried merchandise in his duffel bag, law enforcement sources said.
Clothing or cardboard was used to cover the bodies of the murder victims, police have said.
A man, later identified as Perrone, was captured on video last Friday at 6 p.m. within a block and a half of the latest crime scene, a women's boutique on Flatbush Avenue. The latest victim, 78-year-old Rahmatollah Vahidipour, was killed sometime between 4:30 p.m. and 7:11 p.m. Friday.
A second video, from Aug. 2, appeared to show "John Doe Duffel Bag" near the Bensonhurst shop where Isaac Kadare, a Jewish man from Egypt, was murdered with the same .22 caliber gun that was used to kill Vahidipour, sources told ABC News.
On July 6, clothing store owner Mohamed Gebeli, an Egyptian Muslim, was killed inside Valentino Fashion in Bay Ridge. Gebeli was shot in the neck and was found with several pieces of clothing on top of him. Police said $383 in receipts was missing, but $1,500 was found inside a cabinet.
The trio of killings took place within a five-mile radius. Each occurred at a small shop that lacked security cameras, and each victim was over 50 years old and Middle Eastern, police said. It was not clear whether the victims had been robbed.
Police and prosecutors declined to discuss motives or any information the suspect might have disclosed during questioning.
Perrone will be arraigned within the next 24 hours and charged with murder in the first and second degrees for each of his three victims, according to the Brooklyn District Attorney's Office. The first degree murder charges apply under state law because three or more individuals were killed in the state in less than a two-year period under similar circumstances.
However, officials do not consider the severity of the charges crucial in the case because Perrone will turn 64 Thursday, so any conviction essentially will mean life in prison.
ABC News' Michael S. James and Kevin Dolak contributed to this report.