The ghastly terror attack by a suicide bomber at a theatre show in Manchester which was mostly attended by young men and women and some children highlights the vulnerability of people in the western world to extremist activity and the inhumanity of the perpetrators.
The latest arrests take the total number in the United Kingdom to six, including Abedi's brother Ismail. Under British law, a person can be taken into custody in a terrorism investigation and held up to 14 days without charges.
His friend Ryssell Hayward said: 'We got the news last night that our wonderful iconic and lovely Martyn didn't survive.
In 2011, Abedi returned to Libya during the mass uprising that descended into a civil war and ended with Gadhafi's ouster and death.
The father of the Manchester bombing suspect says that his son is innocent.
A raid was taking place at an address in central Manchester on Wednesday afternoon.
Her comments came as security was being tightened and police were investigating a "network" over the attack, which was carried out at the Manchester Arena on Monday evening.
"The investigation into the terrorist attack in Manchester is large-scale, fast-moving and making good progress", Rowley said.
The official threat level in Britain was raised late on Tuesday for the first time in a decade to its highest level, "critical", meaning an attack could be imminent.
On Wednesday, French Interior Minister Gerard Collomb told a television interviewer that Abedi had travelled to Syria and had ISIS links.
British police have been tight-lipped, and have not taken the step of reassuring the public that a suspected bombmaker is among the five people now in custody.
Abedi was known to British authorities prior to Monday night's attack, CBS News reported.
Omar Alfa Khuri, who lives across the street, said he was awakened at 2:30 a.m.by a loud noise and saw police take away the father of the family that lives there in handcuffs.
"I have been very clear with our friends that should not happen again", Rudd said.