PITTSBURGH (WASHINGTON POST) - The quiet central Pittsburgh neighbourhood of Squirrel Hill is home to one of the most concentrated Jewish communities in the country.

The tree-lined community - a historical religious safe haven - is usually busy with activities on the weekend, buzzing with pedestrians, baby strollers and dog walkers.

This Saturday (Oct 27), though, the streets were desolate.

As the local synagogues convened for morning prayers, Pittsburgh's oldest synagogue, the Tree of Life congregation, was struck by what the Anti-Defamation League called "likely the deadliest attack on the Jewish community in the history of the United States".

A gunman, identified by the authorities as 46-year-old Robert Bowers, opened fire with an assault rifle, killing 11 people, injuring six others - and leaving the community in shell-shocked silence.

The synagogue's rich history dates to the late 1800s, according to Ms Lynette Lederman, executive assistant to City Councilman Corey O'Connor and former president of the congregation.

Over the years, demographics have changed, but Pittsburgh's Jewish population continues to boom. Half of them - just short of 50,000 people - live in Squirrel Hill, according to a recent study done by the Jewish Federation of Pittsburgh.

"It's become one of the most diverse places in the country," Mr O'Connor said. "Now we're so infused by young families who want to live in neighbourhoods like Squirrel Hill... demographically, we are very diverse, but traditions are held very closely."

The Jewish Federation of Greater Pittsburgh has given funding to the Jewish Community Centre and the Jewish Association on Ageing, according to Ms Lederman, who is also a board member of the latter.

Born and raised in Pittsburgh, Mr Elliot Dinkin was reading in his office on Saturday morning, when his wife hurried in to tell him about the shooting.

"I thought it was a mistake," Mr Dinkin, 68, told The Washington Post. Then he rushed downstairs and saw the news on television. His first thought: Was his 95-year-old father OK?

Now retired, Mr David Dinkin was once the executive director of Tree of Life. Mr Elliot Dinkin was relieved to learn that his father, who rarely missed a Saturday service, had decided to stay home that day because he wasn't feeling well.

Mr Elliot Dinkin said that when he was a child, Squirrel Hill was a nurturing environment that centred on the Jewish Community Centre and the Hebrew day school.

He said that the neighbourhood evolved over the years. Although the vibrant Jewish community has not changed, he said, individual synagogues have declined in membership.

Tree of Life, for example, now rents out space to other, smaller-growing synagogues.

"There was a drop-off in the population where they couldn't sustain themselves. When I was a kid, it was unheard of because the conservative synagogue was large enough endure on its own," he said, adding that Tree of Life's congregation mirrored those of nearby synagogues.

The Tree of Life building houses three synagogues and has multiple communities that worship simultaneously. On Saturday, there were three ongoing services when the gunman attacked.

According to an article earlier this year in the Post-Gazette, Pittsburgh's Jewish population is less tied to organised religion than previous generations.

Most Jews identify by religion, but far fewer belong to a synagogue, the article said, adding that the Reform and Conservative denominations have experienced the most significant change.

Still, even to newcomers, Squirrel Hill remains well-known as a centre of Jewish culture.

Mr Nikhil Srivasdava, 32, and his wife Neha Aeri, 30, moved from India to Pittsburgh several years ago.

Like Mr Dinkin, the couple experienced the dark side of American life on Saturday, receiving an emergency message from the University of Pittsburgh, where Ms Aeri is enrolled in business school, warning them to stay indoors.

Then they saw police cruisers and armed officers blocking off roads. "We've never seen anything like this in this neighbourhood. This is one of the, I would say, safest and nicest neighbourhoods in Pittsburgh," Mr Srivasdava said. "We are not sure what to make of it."

Shootings like this, he said, don't happen in India.

By rare chance, Mr Arnold Freedman, a 91-year-old psychologist and Tree of Life congregant, did not attend services on Saturday. Down the block from Mr Srivasdava, he observed the police commotion, too.

"The next thing I knew, I saw the whole street was filled with police cars," he said. "I started looking around; I didn't know what was going on."

Mr Freedman turned on the news and then began receiving calls from concerned friends and family members.

"I'm just lucky that I'm OK," he said. "The full impact hasn't really hit me yet. Chances are, I know of some people who were there, who were possibly killed or injured."

Mr Freedman said he was frightened by the depth of anti-Semitism said to have been espoused by the alleged gunman.

"I'm just terribly saddened by it," he said. "There's barely a day that goes by that you don't hear about people shooting somebody for something."