59-year-old Cecil Carabador was fatally struck as he stood near ScotiaBank San Juan just before 10pm on Saturday.
According to reports, two men with bandanas over their faces entered a restaurant near Scotiabank in San Juan and ordered the cashier to hand over the money.
An off-duty police officer who was in the restaurant at the time attempted to foil the robbery by drawing his weapon and ordering them to stop.
A shootout followed, which spilt out of the restaurant onto the pavement. Carabador was hit during the gunfight and the bandits escaped.
He was taken to hospital where he was pronounced dead.