Off-Duty A.T.F. Officer Is Killed While Intervening After Robbery An off-duty special agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives was fatally shot on Saturday afternoon when he, along with at least one other law enforcement officer and a retired officer, tried to stop a robber who had just held up a pharmacy on Long Island, the authorities said. The robber was also killed, according to the Nassau County Police Department. Details of the shooting, which occurred outside Charlie's Family Pharmacy on Merrick Road in Seaford, remained murky on Saturday night as the authorities seemed unsure how it unfolded and who fired the fatal shots. The officer killed, John Capano, an explosives specialist who was in his 40s and had been a special agent for 23 years, was assigned to the bureau's Long Island office, said Joe Anarumo, a special agent with the bureau. He was married, lived in the Seaford area and had two teenage children. "Today, doing his job in an off-duty capacity, he intervened in an armed robbery and subsequently was shot," Special Agent Anarumo said, adding, "He was a hero." On Saturday, just before 2 p.m., a lone man walked into the drugstore and announced a robbery, said Officer Maureen Roach, a Nassau police spokeswoman. She did not say if the robber was armed. "He was demanding OxyContin and cash," said Lt. Kevin Smith of the Nassau County police, adding that he did not know how much was stolen. There were customers in the store at the time of the robbery, Lieutenant Smith said, though he said he did not know how many. A law enforcement official, who spoke on the condition of anonymity because the case was unresolved, said the preliminary accounts indicated that after the robber left the pharmacy, he went to a parking lot, and people pointed him out as a suspect. Special Agent Capano then confronted the man. Somehow in the struggle between Special Agent Capano and the robbery suspect shots were fired, "and that is when the agent is shot," the official said. Next door to the pharmacy is a deli the official said was believed to be owned by a retired Nassau County police officer or detective. Some people from the pharmacy went into the deli next door and told the people there what had occurred. Also in the deli at that moment was an off-duty member of the New York Police Department, the official said. "They come out and see these guys struggling," the official said. The official said it was believed that either the retired Nassau officer or the off-duty New York officer shot at the struggling men. The suspect was hit by gunshots and was fatally wounded. It is not clear if Special Agent Capano was shot then or if he had been shot earlier in the struggle with the suspect. Ryan Lecertosa, 24, was on his way home when he drove past the pharmacy Saturday afternoon and heard several gunshots. He said he saw a large man in front of the shop with a blood-soaked shirt. "He was holding his chest, and then he collapsed," Mr. Lecertosa said, adding that the man was instantly surrounded by about six people.