By Allan Lengel

An off-duty ATF agent was shot and killed Saturday afternoon in Nassau County in Long Island, N.Y. while struggling with a robbery suspect outside a pharmacy where the agent was going to pick up his father’s cancer medication, according to authorities and the Associated Press.

Agent John Capano, a 23-year veteran of ATF, was off duty and in the Seaford, N.Y. shopping center’s parking lot at about 2 p.m. when the suspect entered the pharmacy and robbed it of OxyContin and cash, according to ATF.

Several patrons ran out of the store and pointed out the robbery suspect. ATF said agent Capano immediately confronted the suspect, began struggling with him and attempted to disarm him.

A retired Nassau County police officer and an off-duty New York City police officer who were in a deli next door were also alerted, ATF said.

Both came out of the deli and saw the men struggling and fired, killing the suspect, which AP identified as James McGoey. Agent Capano was also fatally wounded during the confrontation. It was unclear from the ATF press release and media reports as to who actually shot the agent.

Agent Capanois is survived by a wife and two children.

To honor the memory of  Capano, ATF buildings that fly the ATF flag have been authorized to lower the flag to half staff from January 1 to the  day of his interment, from sunrise to sunset.