(Karla Adam,Sarah Parnass/The Washington Post)

For years, Finsbury Park was considered a hotbed of Islamist extremism. A relatively deprived immigrant neighborhood in North London, it was the home of the Finsbury Park Mosque — infamous for housing the radical Egyptian cleric known as Abu Hamza al-Masri, who was later extradited to the United States and found guilty of terrorism charges.

But like many of its surrounding neighborhoods, the area has rapidly gentrified in recent years, arguably becoming both more diverse and tolerant at the same time. Kebab shops sit comfortably next to cafes serving flat white espressos. Finsbury Park Mosque has undergone its own dramatic reforms over the previous decade, too, with its extremist edges stripped away.

Perhaps the biggest remaining controversy surrounds which soccer team to support — nearby Arsenal being the local favorite.

Yet it was in this contemporary Finsbury Park that a van plowed into a group of Muslim worshipers in the early hours of Monday morning, leaving one dead and injuring 10 others outside the nearby Muslim Welfare House. Police say the incident is being treated as a terrorist attack, and witnesses say the alleged attacker shouted that he wanted to kill Muslims.

Many locals lingered until midmorning by the cordoned-off scene, shocked not only that yet another apparent terrorist attack had hit Britain, but also that it appeared to have targeted Britain’s Muslim community. Some expressed frustration with the police response and bristled at any association with religious extremists.

Britain's opposition Labour Party leader, Jeremy Corbyn, meets local people in Finsbury Park Mosque, near the scene of Monday’s attack. (Stefan Rousseau/Pool photo via Reuters)

“It’s unfair to the Muslim community,” said one young man who gave his name as Adil Rana. “We don’t feel safe anywhere. We don't feel safe walking the streets or going to the mosque.”

Others suggested that the area’s perceived links to Islam gave rise to threats. “It’s always been a target,” said Sultan Ahmed, a 35-year-old aid worker. “This area’s always been a target.”

The neighborhood’s reputation for religious extremism was acquired in the 1990s, after the Finsbury Park Mosque was opened to cater to a historically Irish neighborhood’s booming Islamic community. The mosque was soon infiltrated by Mustafa Kamel Mustafa, the charismatic extremist preacher better known as Abu Hamza al-Masri. The Egyptian-born cleric served as an imam from 1997 onward and may have attracted attendees such al-Qaeda “shoe bomber” Richard Reid, whose attempt to blow up a Miami-bound flight was thwarted in December 2001.

As one former White House counterterrorism official once put it, London had become “the Star Wars bar scene” for Islamist radicals before the Sept. 11, 2001, attacks in New York and at the Pentagon. The Finsbury Park Mosque was perhaps the most obvious example of that setting in action.

“You really had a mosque there that was essentially a way station for international jihadism,” said Raffaello Pantucci, director for international security studies at the Royal United Services Institute in London. “It was a place where people could rest, recuperate and everything else.”

Things changed after 2003, when the mosque was raided by police as part of an investigation into an alleged plot to produce ricin poison. The mosque was closed, and Masri was extradited in 2012 to the United States, where he was sentenced to life in prison after being found guilty of 11 terrorism-related charges.

Finsbury Park Mosque reopened in 2005 with new management that sought to put this past behind it. On the mosque’s website, there is talk of a “new era” with an emphasis on the “true teachings of Islam as a religion of tolerance, cooperation and peaceful harmony amongst all people who lead a life of balance, justice and mutual respect.”

Pantucci said this shift has largely been a success. “I don’t think we’ve seen the same sort of problems by any stretch of the imagination,” he said. “Now, its just a big mosque in London.”

The mosque now claims to attract almost 2,000 worshipers, and in 2014 it won a prestigious award for its services to the community, though its past links to extremism made it a target for criticism from Britain’s far right.

Part of this shift was in the context of a broader evolution of Islamist extremism in Britain, with mosques heavily surveilled and no longer the logical choice for recruitment and radicalization. But it was also the work of Muslim community leaders, in partnership with the London Metropolitan Police Service’s Muslim Contact Unit and local member of Parliament Jeremy Corbyn.

Pantucci also said that the Muslim Welfare House, aligned with the Muslim brotherhood, also played a significant role in the helping the Finsbury Park Mosque rid itself of extremism. After Monday morning’s incident, witnesses said, the imam at this nearby Muslim center and mosque stopped worshipers from attacking the man who had been driving the truck.

“He said hand him over to the police,” said Rana. “I feel he did the right thing.”

Other members of the community rushed to the site of the attack to help, too. Eli Feldman, a 29-year-old Orthodox Jew who lives in nearby Stamford Hill, said he headed over early in the morning after hearing what had happened.

“We live together with the Muslim community,” he said. “What the terrorists want is to divide, but we actually came to support.”

Later in the morning, a woman who gave her name only as Allison and said she was a retired schoolteacher arrived with a homemade sign that read, “Leave our Muslim neighbors alone.”

Allison said she has lived in Finsbury Park for at least 35 years and seen the neighborhood change over time. “I feel really hurt that this has happened near here and very angry really,” Allison said. “This is not a war. It’s just idiots.”

But some worried that the attack would still cause further problems for Finsbury Park’s Muslim community during the holy month of Ramadan.

“Everyone’s focused on spiritual upliftment,” said Ahmed. “This time next week we should be celebrating Eid. It should be a joyous occasion and a celebration. Now it’ll turn into a really somber day.”