UPDATE: Police in New York City arrested Salvatore Perrone, 64, over the Thanksgiving weekend and charged him with using a sawed-off .22-caliber rifle he carried in a duffel bag to kill three Brooklyn shopkeepers in the last four months. People who saw surveillance footage of Perrone, who’s white, pointed police to Perrone, despite an artist’s drawing that depicted a balding black man as the suspect. Dubbed “Son of Sal” by his neighbors for his annoying conduct, Perrone may have had previous contact with his victims through his work as a fabric and garment salesman who wanted to start his own clothing line, according to media accounts. He was charged with three counts of second-degree murder and one count of first-degree murder, an additional count filed because he allegedly killed three people within two years.

Hate crime detectives in New York City are joining the investigation into three unsolved killings of Brooklyn business owners in the past four months – crimes believed to have been carried out by a serial killer.

All three victims were shot with the same .22 caliber handgun, all three were immigrants from the Middle East, all three worked alone without security cameras and all three businesses have the number 8 in their address, authorities say.

The latest victim, Rahmatollah Vahidipour, 78, a Jewish immigrant from Iran, was fatally shot Friday in his business, She She Boutique on Flatbush Avenue in Brooklyn. That homicide followed the Aug. 6 killing of Isaac Kadare, 59, a Jewish immigrant from Egypt, who was fatally shot in his Bensonhurst store, Amazing 99 Cent Deal.

The spree began with the July 6 killing of Mohammed Gebeli, 65, an Egyptian immigrant and a Muslim, found murdered in his business, Valentino Fashion Inc., in Bay Ridge. Detectives are “exploring a few similarities among the three murders,” The New York Times reported in Sunday’s editions.

Cash was stolen in the first two homicides, but not in the most recent murder, authorities say. Investigators assigned to the Police Department’s Task Force on Hate Crimes have been brought in to assist with the investigation, the newspaper reported. But Paul J. Browne, the department’s chief spokesman, said there was at this point no clear evidence indicating the three murders were bias crimes.

However, New York Police Commissioner Ray Kelly said there is a reason hate crime experts have been added to the investigation. “The possibility of a bias motive here is something that can’t be excluded,’’ Kelly told a reporter for NBC 4 New York. FBI behavior analysts also are now assisting the investigators, according to various media reports.

Police released a composite drawing of the suspect, described as a 5-foot-5-inch tall black man, 140 pounds and wearing sunglasses. Another similarity in the three murders is each of the businesses has the number 8 in its address. However, investigators are “downplaying the theory that the killer is obsessed with numerology,” the New York Daily News reported.

“There is nothing to indicate anything beyond coincidence in the numbers,” a police source told the newspaper. Police are telling storeowners to not work alone and consider adding security cameras. The three homicides are frightening other business owners, according to media outlets.

“Pretty nerve-wracking that a serial killer is on the loose in Brooklyn,’’ Howard Prince, the manager of a business near the She She Boutique told NBC 4 News. “I mean that’s not the part that concerns me,’’ he said. “The part that concerns me is you take somebody’s life that’s 78-years-old, for no reason”