The man responsible for bombing a packed pop concert in Manchester, killing 22 people, is believed to be a British-born man of Libyan descent.
He was named by police as 22-year-old Salman Abedi, and died at the Manchester Arena venue on Monday night when the blast went off at the end of the concert by US singer Ariana Grande.
Media reports said he was born in the north-west English city of Manchester to Libyan parents, who fled their home country to escape the regime of former dictator Moamer Kadhafi.
The Islamic State group claimed the attack, saying that "one of the caliphate's soldiers placed bombs among the crowds".
Police say they are now urgently seeking to confirm whether Abedi worked alone, or acted as part of a wider network.
Abedi's family have lived in the Fallowfield area of south Manchester for at least 10 years, according to the Daily Telegraph newspaper,
Armed police raided an address in the modestly well-to-do area earlier on Tuesday, carrying out a controlled explosion to gain entry.
A 23-year-old man was also arrested in the south of the city in connection with the attack.
Fallowfield resident Peter Jones, 53, described the area as "quiet and safe".
Jones told AFP that he was "shocked" and "surprised" when he heard that the suspect was from there.
The Guardian reported that Abedi was known to the police and security services.
"He was such a quiet boy, always very respectful towards me," one member of Manchester's Libyan community told the newspaper.
"His brother Ismael is outgoing, but Salman was very quiet. He is such an unlikely person to have done this."
The newspaper said Abedi's father is well-known in the community, and worked as an odd-job man, but is thought to be currently in Tripoli.
The Telegraph said Salman was the second youngest of four children, including another son and one daughter.
Manchester is home to Britain's largest Libyan community, which numbers about 16,000 in total, according to the BBC. It was a focus of celebrations at Kadhafi's fall in 2011
"We understand that feelings are very raw right now and people are bound to be looking for answers," Chief Constable Ian Hopkins of the Greater Manchester Police force said.
"However, now, more than ever, it is vital that our diverse communities in Greater Manchester stand together and do not tolerate hate," he told reporters.
Manchester's many religious and ethnic communities came together on Tuesday evening to hold a minute's silence and vigil.