Forces were warned Abedi was a threat

SECURITY agencies were warned several times that Salman Abedi was a dangerous extremist but failed to arrest him before he detonated a “big and sophisticated’’ suicide bomb that killed 22 people.

The warnings to MI5 and police were revealed as the murderer’s father and younger brother were arrested in Libya and police discovered a rented flat in central Manchester that they believe was used as a bomb factory.

Forensic photographs of the bomb debris leaked from US intelligence to the

York Times show it packed with projectiles and built into a backpack, which Abedi detonated with his left hand.

Security officials said it was a “sophisticated’’ device built in the UK.

Police in Manchester have now detained six people as part of their inquiries.

They believe Abedi, 22, a university dropout who was born in the UK, was acting as part of a terrorist cell that may have links to international jihadists.

“It is very clear that this is a network we are investigating,” said Greater Manchester’s chief constable, Ian Hopkins.

In a dramatic day yesterday:

POLICE in the Libyan capital of Tripoli seized Abedi’s father, Ramadan, 51, and arrested his young brother Hashem, 20 at gunpoint.

THE third Abedi brother, Ismail, 23, remained in custody in Manchester after being arrested on Tuesday morning.

THREE people have now been detained by Greater Manchester police in south Manchester, a fourth in Wigan and a fifth in Nun- eaton, Warwickshire, while a woman detained in north Manchester was released without charge.

AN Airbnb rented flat in Granby Road, in central Manchester, was identified as the venue where chemicals to make the bomb were mixed. POLICE believe a second, as yet unidentified, venue was used to assemble the bomb, which comprised metal nuts and screws in a metal box,

h idden within a Karrimor backpack.

ABEDI rented the flat a few days before the attack and stayed there until 7pm before leaving for the Manchester Arena, where Ariana Grande was holding a pop concert. POLICE were investigating potential links with international terrorists including Mohamed Abrini, the socalled Man in the Hat, who was connected to the attacks in France and Brussels in the past two years.