New York Pharmacy Shootout Leaves Suspect, ATF Agent Dead The pharmacy was held up by a man seeking prescription medication.

Dec. 31, 2011 -- A shootout at a suburban New York family pharmacy left a suspected robber and an off-duty federal agent dead in a confused shootout that took place as the robber fled, authorities said.

Charlie's Pharmacy in Seaford, Long Island, N.Y. was held up by a man seeking prescription medication and cash this afternoon.

As the suspect fled he was confronted by three people - two off-duty law enforcement officers and a retired law enforcment officer, officials said.

A shootout ensued and the suspect was killed.

John Capano, a 23-year veteran with the Bureau of Alcohol, Tobacco, Firearms and Explosives was also killed.

Capano was an explosives expert with multiple tours in Afghanistan and Iraq training soldiers to defuse IEDs, federal authorities said.

According to early accounts, it appeared that Capono shot the suspect – who was believed to be armed as he fled the drug store--a family business for several generations, local cops said. Then Capano himself was shot and killed by an off duty officer.

"Both guys on the floor. Blood all over the place and apparently one guy was dead and drugs were laying all over the floor," eyewitness Matthew Hipp told ABC News New York station WABC.

Authorities are investigating the crime scene to determine the exact timeline of events.

ABC News' New York Station WABC contributed to this report.