An off-duty special agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives was fatally shot on Saturday, when he attempted to stop an armed robbery at a Long Island, N.Y., pharmacy.

Special Agent John Capano, a 23-year veteran and explosives expert, was at Charlie's Family Pharmacy in Seaford when the shooting occurred, reports the New York Times.

Details of the shooting are still murky, but police believe a retired Nassau County Police officer and off-duty New York City officer may have also intervened. The suspect was also fatally shot.