They strode into the restaurant supply store in Harlem shortly after 3 p.m. on Thursday, four young men intent on robbery, one with a Glock 9-millimeter pistol, the police said. The place may have looked like an easy mark, a high-cash business with an owner in his 70s, known as a gentle, soft-spoken man.
There were no customers in the store, only Mr. Augusto and two employees, a man and a woman. The police said the invaders announced a holdup, approached the two employees and tried to place plastic handcuffs on them. The male employee, a 35-year-old known in the community as J. B., struggled with the gunman, who then hit him on the head with the pistol.
Watching it happen, Mr. Augusto, whom neighborhood friends call Gus, rose from a chair 20 to 30 feet away and took out a loaded Winchester 12-gauge pump-action shotgun with a pistol-grip handle. The police said he bought it after a robbery 30 years ago.
The first shot took down the gunman at the front. He died almost immediately, according to the police, who said he was 29 and had been arrested for gun possession in Queens last year and was the nephew of a police officer.
Mr. Augusto’s other two blasts hit all three accomplices, who stumbled out the door, bleeding.