But even before yesterday's attack, counter-terrorism operations had focused on the small part of the city's south.
Experts say Manchester's hidden radicalisation problem is not unique to the city.
"What we have seen recently is the emergence of clusters where groups of people - who often live close to one another - radicalise relatively quickly," said Raffaello Pantucci, the director for international security studies at the Royal United Services Institute in London. "This isn't only happening in London or Manchester, but also in much smaller towns."
The British Government has taken action as networks of extremists have developed across the country. Over the past few years, several laws have been passed to give authorities greater powers to arrest and prosecute attack suspects. Security services say they foiled 13 major terrorism plots between 2013 and March of this year. But at times, the expansive operations have come at a high price.
In 2010, authorities in the city of Birmingham set up surveillance cameras to monitor Muslims suspected of terrorism. But critics argued at the time that the operation placed all Muslims under suspicion. By the time the project was eventually stopped, it had damaged relations between counterterrorism officers and the city's Muslim community. News of the surveillance scheme fed suspicion of authorities nationwide, officials say.
Manchester "has avoided making such mistakes," said Jim Bonworth, a retired chief inspector with the Greater Manchester Police. "The British police very much relies on tips by community members. We cannot afford to lose their trust."
Manchester's experience shows that even praised community policing efforts struggle to prevent the radicalisation of closed social circles across Britain.
"In the past, such radicalisation processes have often taken place in mosques," Pantucci said.
More recently, however, authorities have largely lost the ability to monitor terrorism suspects during their visits to mosques or community centres. Instead, groups of friends or acquaintances are meeting in apartments, making it nearly impossible for Britain's stretched security services to monitor suspects, a dynamic that could explain the seemingly sudden emergence of groups of radicalised individuals in places such as southern Manchester.
Members of the community said they were distraught by the police operations in their districts after the attack, which was claimed by Isis (Islamic State).
"I sometimes saw him walk into his building alone or with friends," said 32-year-old Neville Edwards, a neighbour of the suspect. "But nobody here ever really talked to him."
In Manchester's Libyan community, Abedi was not unknown, however.
A man who identified himself as a friend of the Abedi family said many of the Libyans who live in the area fled the Government of Muammar Gaddafi and supported the uprising against his regime.
"The Libyan community was standing by the rebels," he said, speaking on the condition of anonymity for security reasons.
"I saw the boy here and there and we were even once on the same flight to Libya, but we weren't close," he said of the suspect. "I am more from his father's generation."
"We don't know what happened to him or why he committed this attack on behalf of Daesh," he said. "But we are worried that this might make us Libyans look very bad."
A taxi driver from the area said he had never seen Abedi but had witnessed the aftermath of the attack. The man said he was parked outside the venue where the concert was taking place when he heard the explosion. He then picked up two survivors.
"This is such a cosmopolitan city, but there are circles and groups of people which are extremely closed to outsiders," said the man. "That is where teenagers or young men and women become radicalised. If it can happen here, it can happen anywhere."
Pointing at a school in front of him, he added, "That's the school two twin girls attended until they travelled to Syria to join the Islamic State." Their case made international headlines.
Three years later, TV satellite trucks are on the same street again.
Abedi lived several hundred metres away from the school, according to his former neighbours.
