OLD BRIDGE, N.J. – A New Jersey supermarket employee opened fire at the closed store early Friday, killing two co-workers and himself, a prosecutor said.

The 23-year-old man left a Pathmark in Old Bridge Township around 3:30 a.m. and returned a half-hour later with a handgun and an AK-47 assault rifle, Middlesex County Prosecutor Bruce Kaplan said.

The man fired the rifle at the first workers he saw, killing an 18-year-old woman and a 24-year-old man as other workers hid, Kaplan said. At least 16 rounds were fired, some breaking the front windows.