Holdup at N.J. Post Office Leaves 4 Dead, 1 Wounded : Crime: No suspects are in custody in the armed robbery. The injured victim is listed in critical condition with wounds to the head.

Four people were slain by gunfire Tuesday during a holdup at a tiny satellite post office in this suburb of New York City.

A fifth victim was airlifted by helicopter to University Hospital in nearby Newark, N.J., and was listed in critical condition with wounds to the head. He was identified by police as David Grossman, 45.

No suspects were in custody in the slayings, and authorities were conducting a door-to-door search Tuesday night.

Police Chief Thomas Russo said that two of the victims were postal employees and two were customers, as was Grossman.

Police were summoned by a postal worker who entered the Upper Montclair branch around 5 p.m. EST and saw a body on the floor.

There were reports for a time that some postal workers and customers were held hostage during the holdup and managed to escape after police knocked down the front door of the small white building containing the postal facility. But these reports apparently were sparked by the sight of children and their parents fleeing a physician’s office next to the post office after police said it was safe.

“I saw people running and police with guns drawn standing behind their cars,” said Tom Maw, the manager of the nearby Watchung Chinese Restaurant.

“I first learned there was trouble when a man ran into my store and said: ‘There’s a big holdup at the post office and cops are everywhere,’ ” said Om Singhal, the proprietor of the Townhouse Liquor Store.

“He (the gunman) is at large. He went out the back,” said Frank Danieli, the owner of Danieli’s Restaurant. “Only two people work at the post office.”

Bill Murphy, who works at a bookshop a few stores down from the post office, said he heard what may have been three shots.

“I thought it was a car backfiring. Then someone came in and told us what happened,” Murphy said.

The shooting shocked this community of gracious Victorian homes 15 miles west of New York City.

“I am sure I know some of the employees,” said Buddy Tierney, 27, a bartender who has lived in Montclair his whole life.

“Montclair is residential. Hard-working people come here to get away from the city. I am very shocked and surprised and sad for the victims and their families. Montclair is a tight-knit community and everyone here knows everyone else’s first name,” he said.

Montclair is a town of mixed-income families with about 38,000 residents. The post office stands amid the Watchung Plaza shopping district and is across the street from the New Jersey Transit railroad station.

Postmaster General Marvin T. Runyon Jr. said in a statement that he was “shocked and saddened by the shootings” and that the events “underscore how vulnerable we all are in a society today where guns and violence have become the norm.”

Goldman is a Times staff writer and Olen is a special correspondent. The Associated Press contributed to this story.