The gunman was identified as Terence Tyler, a 23-year-old former Marine who started working at the Pathmark store in Old Bridge Township about two weeks ago.
He apparently had an argument with someone at the store, then returned and fired at least 16 rounds at his colleagues. An 18-year-old woman and a 24-year-old man died.
There were 12 to 14 workers in the store, which was closed at the time of the shooting. Officials said the suspect, dressed in camouflage and armed with at least two guns, fired the rifle at the first workers he saw. He shot himself as police approached him.