LONDON/WASHINGTON - A second bomb could still be out there, British reports said on Friday (May 26) as police investigate whether the Manchester bomber carried out his attack alone.
Police arrested a man on Friday in the suburb of Moss Side, the 10th person to be taken into custody in connection with Monday (May 22) night’s attack. Eight men are in custody now after a man and a woman were released without charge, Greater Manchester police said in a tweet.
On Friday morning, police raided a barber shop in Moss Side as part of their investigation, with a police cordon placed around four properties - a hardware shop, a pharmacy and a cafe, beside the barber shop - reported The Guardian. It was unclear if any additional arrests were made.
On Thursday, raids on homes across Manchester including the bomber Salman Abedi's residence on Elmsmore Road, Fallowfield, and a rented apartment he was staying in at Granby House, Granby Row, uncovered a stash of bomb-making material.
The rented apartment in central Manchester is less than 3.2km from Manchester Arena, where Monday night's attack unfolded.
It is not clear if the "bomb factory", as the Mirror called it, was found on both properties or one, but the discovery has stoked fears that a second or third bomb could be out there, some British reports said.
A security source told the Telegraph: "The worry is there was enough to build two or three bombs and we can't rule that out."
Abedi is reported to have been at the flat in Granby House at 7pm on the night of the attack, the Mirror said.
He set off a bomb in the foyer of the Manchester Arena as concertgoers were leaving an Ariana Grande concert on Monday night, killing 22 in the deadliest attack in Britain since 2005, when four Islamist suicide bombers killed 52 in an attack on London's transport system.
Leaked evidence from the crime scene apparently point to a remote mobile-phone detonator to enable someone else to set it off if Abedi backed out at the last minute, The Daily Mail said.
It suggests an accomplice would have watched Abedi as he carried out the attack. Initial analysis points to the fact Abedi did blow himself up.
The bomb used in Monday's bombing used the same explosive as those set off in Paris and Brussels attacks, suggesting a possible link to the same terrorist network, a US lawmaker has said.
Republican Michael McCaul, the chair of the US Congress Homeland Security committee, said the bomb suggested a "level of sophistication" that implied its maker or makers may have had foreign training.
Abedi used TATP or triacetone triperoxide, an explosive used in the November 2015 attacks in Paris and the Brussels attack in March 2016, The Guardian reported.
More than 130 people were killed in the Paris attack and 32 civilians died in Brussels.
TATP was also used in the July 7, 2005 London bombings.
The substance can be made from household chemicals but is unstable and unreliable.
The evidence suggested that it was not a "lone wolf" situation, Mr McCaul said.
Images obtained by The New York Times newspaper showed a detonator Abedi was said to have carried in his left hand, shrapnel including nuts and screws and the shredded remains of a blue backpack.
The detonator appeared to have a small circuit board soldered inside one end.
Images of metal nuts and screws propelled by the blast, and of damage nearby, show that the bomb's makeshift shrapnel penetrated metal doors and left deep scuffs in brick walls, The New York Times reported.
This indicated a powerful, high-velocity charge, and of a bomb in which its shrapnel was carefully and evenly packed.
An official said one element of the investigation was whether Abedi was part of a larger terror cell.
He likely received some ISIS training in Syria in the months before the attack, according to information gathered in the preliminary investigation, a US official told CNN on Thursday.
A relative told AFP that Abedi had travelled to Manchester from Libya four days before the bombing, transiting in Istanbul and Dusseldorf.
The next day, he was caught on CCTV buying a Karrimor backpack at a mall, The Telegraph said.
His father Ramadan and younger brother Hashem have been detained in Libya, with officials there saying the brother was aware of the planned attack.
They said both brothers belonged to ISIS, while the father once belonged to a now-disbanded militant group with alleged ties to Al-Qaeda.
A British official confirmed Abedi had been on the intelligence radar before the massacre. The MI5 domestic security service is managing around 500 active investigations, involving some 3,000 "subjects of interest", the senior government ministry source said.
"Abedi was one of a larger pool of former SOIs whose risk remained subject to review by MI5 and its partners," he said.