The public library in a small New Jersey town where police shot a man dead on Friday partially reopened on Monday, though it was far from business as usual.

The quiet town of Lyndhurst in northern New Jersey, less than 30 minutes across the water from the skyscrapers and big-city buzz of Manhattan, is reeling from the incident that “came out of the blue”, according to residents and business owners.

But unlike in larger cities or suburbs that have erupted in civil unrest since the killing of an unarmed black teenager by a white police officer in Ferguson, Missouri, last summer, Lyndhurst has remained calm. And residents of the prosperous, growing and largely white town who spoke to the Guardian appear ostensibly sympathetic to the police since Friday’s death.

Kevin Allen, 36, was shot upstairs at the community library on Friday afternoon, according to police chief James O’Connor, after he resisted arrest for a probation violation and pulled a knife on an officer who followed him into the library and confronted him.

No details about the officer who first confronted Allen and a second officer who came to his assistance have been released, except that O’Connor said that the use of pepper spray and the officers’ batons had failed to subdue the man and the police had “no choice” but to shoot him dead.

Allen was African American and had a long arrest record, but other details of his life and the exact sequence of events in the library have yet to emerge.

Resident Craig Delora said: “There are conflicting reports, but I was told that he started to get very, very belligerent with the police and he pulled a knife out. There was a little girl there who was getting close to him. He did not use the knife on her, it wasn’t a hostage situation, she was just nearby and the police were telling him to stop and get down and he lunged at one of the cops and they had to shoot him.”

Delora admitted he was not at the library at the time but had been told the account of a library worker who had witnessed the incident.

The library, which is normally open on Saturdays, was closed the day after the incident, but re-opened on Monday, with just a handful of residents turning up amid frequent rainstorms.

Staff said they had been instructed not to talk because of the investigation into the incident, which is being handled by Bergen county prosecutor John Molinelli, based at the courthouse in the county seat of Hackensack, 20 minutes away.

The upper floor of the library was cordoned off. A reporter who ascended the stairs was turned away by staff who said the approach was caught on security camera.

However, Molinelli said there is no security footage from inside the library where the incident with Allen happened on Friday, although investigators are studying security footage from outside the building.

The library was tranquil on Monday morning, with one or two people returning books, a staff member stocking the shelves and one man sitting to read the newspapers set out on a large table.

“The library has always been a place I went to for calm and quiet and just the thought that something like this happens in a place where you are supposed to feel serene and safe is very frightening,” said Laura Naseef, who works in Chris’ Family pizza restaurant opposite the library and has lived in the town for 25 years.

“This came out of the blue. It’s a very quiet town,” she said. “You don’t expect your law enforcement to have to deal with a situation like this. I feel bad for them, I have a lot of compassion for someone who had to make a decision like that in a second. You see the police cars here going about their business, usually they’re going to a traffic accident but on Friday they were flying in with a huge sense of urgency. It was scary.”

There have been no protests in Lyndhurst about the death of Allen and Naseef said she hopes “nothing blows up”.

She said she had sometimes seen Allen in the pizza cafe and at the Dunkin’ Donuts in the strip mall next to the library during the day and surmised that he was unemployed but, other than that, said he looked like a “regular guy”.

“But things are not always what they seem on the surface,” she said.

The police station is in the same large municipal building as the library, with its entrance on the opposite side.

O’Connor would not elaborate on details he gave on Friday. “I can’t say anything because it is basically my department that is now under investigation,” he said.

The owner of a jewellery store in the strip mall, Mukesh Patel, said he moved to Lyndhurst with his wife from Mumbai, India, 22 years ago and found the town extremely friendly and safe.

“There is never any violence, anything like this, no trouble on the weekends, or with drunks or drugs, or anything. People say hello, there are no race problems, the park near here is beautiful, it’s a family town,” he said.

He said the parking lot at the mall emptied out rapidly as events unfolded on Friday afternoon and the police cordoned off streets.

“The police come in sometimes and they are very nice. I know in some towns they are rude, but not here, not in this town. I was really sad when I heard about what happened in the library, I couldn’t believe it. But thank God it was not something worse,” he said.

Delora said that the incident was a shock to Lyndhurst.

“The police officers involved were rushed to the hospital because they have never used their firearms in their lives. I’ve never seen any run-ins with the cops here, they are very nice and polite. It’s a low crime neighborhood,” he said.

A shopworker, Ben, who preferred not to give his second name, chimed with others who said a citizen death in a violent confrontation with the police was completely out of character for the town.

“It’s really like a one-time incident. There are never problems with the police here. People think it’s justified [the shooting of Allen], because he was going crazy. I feel as though they should not have shot and killed him, it’s like overkill, but maybe there was nothing else to do if it was a knife,” he said.