UK police arrest 'known wolf' in mass murder of 22 at concert

Daily Mail:

This is the dramatic moment anti-terror police swooped to arrest a man over last night's suicide bomb atrocity at Manchester Arena.

Pictures show non-uniform officers wearing masks to conceal their faces arresting a 23-year-old man outside a Morrisons supermarket in Chorlton, south Manchester this morning.

The arrest came hours after a suicide bomber slaughtered 22 and injured 119 after an Ariana Grande concert and as police tried to determine whether the attacker was part of a wider terror cell.

Officers are combing CCTV to determine whether the attacker carried out a 'recce' of the arena before detonating a nail bomb as thousands were leaving the concert at 10.30pm.

Nobody has claimed responsibility for the explosion. But last night, ISIS supporters were celebrating the massacre online while two messages, posted four hours before the attack, appeared to predict the mass killing.
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The suicide attacker is said to have been 'known' to the authorities and anti-terrorist officers are going through hundreds of hours of CCTV footage trying to 'pick him up' during his journey to the arena.

Officers also believe that he will have carried out a 'recce' to the giant venue in recent days and a separate team are studying footage going back into the past week.

Forensic and bomb squad officers are studying the remains of the device recovered so far but initial indications are that the bombmaker had used a 'level of sophistication' suggesting he had received training and not made it from 'a terror recipe' on the Internet.

One security source told MailOnline: 'It is unlikely that if the device was sophisticated that the suicide bomber made it – experience shows that organisations are reluctant to "waste" the expertise of a bombmaker in an attack, preferring to keep him or her for another attack.

'It is therefore highly likely that this terrorist is part of a cell or had a support network and they are the priority.
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There is more.

Since the guy arrested was not the suicide bomber, that does suggest that there was a cell.  For some reason, the UK police are reluctant to admit that the attacks were by Islamic terrorists, but ISIS was crowing about on social media.   The mass murder of noncombatant young people would also fit the MO of Islamic terrorists.