The first killing took place days after the Fourth of July inside Valentino Fashion in Bay Ridge, Brooklyn, where the proprietor was found shot in the neck.  Vahidipour Rahmatollah, 78, was shot and killed on Friday inside his boutique in the Prospect-Lefferts neighborhood in Brooklyn.  The second, a month later, in Bensonhurst, Brooklyn, occurred in a store called Amazing 99 Cent and Up Deals. The shopkeeper there was stabbed in the neck and shot in the head.  Then on Friday, the police responded to a 911 call saying that a man needed help inside the She She Boutique at 836 Flatbush Avenue in the Prospect-Lefferts neighborhood in Brooklyn. Officers found the owner, Vahidipour Rahmatollah, unconscious. He, too, had been shot in the head, and he was pronounced dead at the scene.  On Saturday, the police said the same .22-caliber pistol had been used to kill all three men.  “Ballistic tests completed early this morning indicate that the gun used in the homicide of a 78-year-old merchant on Flatbush Avenue in Brooklyn’s 70th Precinct yesterday was the same one used in similar shooting deaths on July 6 and Aug. 2 in the 68th and 62nd Precincts, respectively,” Paul J. Browne, the Police Department’s chief spokesman, wrote in an e-mail.  All three victims were older men, ranging in age from the late 50s to the late 70s. All three were also of Middle Eastern origin. The first, Mohamed Gebeli, 65, was born in Egypt. So was the second, Isaac Kadare, 59. Police officials said they thought that Mr. Rahmatollah was originally from Iran.  On Saturday afternoon, a woman who said she was Mr. Rahmatollah’s daughter answered the door to his home in Great Neck, N.Y. The woman said her father had three children and nine grandchildren and was to attend a bar mitzvah for one of those grandchildren on Saturday. “He was a great man; he was a very hardworking man,” she said. “I hope they find his killer.”  After Mr. Kadare was killed, detectives found a witness who said he had seen someone fleeing. The police then circulated a sketch that showed a man in his 20s, with a medium build and wearing sunglasses.  The killings have caused unease among merchants in Brooklyn, with some wondering whether similar numbers in the addresses of Mr. Gebeli’s and Mr. Kadare’s shops — both included 7s and 8s — were more than a coincidence. Others suggested that those men had been singled out because they were older and alone.  Police officials said that all possible links were being explored and that they did not know if the same person had used the pistol in all three killings.  Money was taken from Mr. Gebeli’s store, the police said, but it was not immediately known if anything had been taken from Mr. Rahmatollah’s shop.  The She She Boutique was sealed with yellow tape on Saturday afternoon as detectives roamed the area speaking with other store owners and asking them to be careful at night.  Several shopkeepers said they knew Mr. Rahmatollah as an industrious man who worked more than 10 hours a day, at least six days a week, often locking the store by himself after the sun had set.  “He worked all his life,” said Howard Prince, the manager of a fabric shop, Save-A-Thon, three doors away from the She She Boutique. “It’s just horrible.”  On Saturday, Mr. Browne wrote that a reward of $22,000 in each of the killings was being offered for information leading to arrest and conviction.
The police said the three men killed over the past four months were all shop owners of Middle Eastern descent.