Police Investigating Network of Manchester Attack Masterminds

Police say they are investigating a “network” over Monday night’s attack at Manchester Arena, in which 22 people were killed.

An off-duty policewoman was confirmed by police to be among the victims.

Salman Abedi blew himself up outside an Ariana Grande concert.

Four people have been arrested, including the bomber’s 23-year-old brother.

The UK terror threat level is now up to its highest level of “critical”, meaning more attacks may be imminent.

Military personnel are being deployed to protect key sites.

The Palace of Westminster has been closed to the public following police advice, and will not re-open until further notice, its website said.

Home Secretary Amber Rudd said: “[Monday’s attack] was more sophisticated than some of the attacks we’ve seen before, and it seems likely – possible – that he wasn’t doing this on his own.”

It was gathered that the bomber is thought to have been a “mule”, using a device built by someone else.

The victims include Nell Jones, 14, eight-year-old Saffie Roussos, Alison Howe, Lisa Lees, Jane Tweddle-Taylor, 50, Martyn Hett, 29, and Olivia Campbell, 15, .

Kelly Brewster, 32, John Atkinson, 28, Georgina Callander – thought to be 18 – and Marcin and Angelika Klis, a Polish couple from York, have also been named.

Greater Manchester Police chief constable Ian Hopkins confirmed that a serving police officer – off-duty at the time – was among those killed. He did not give her name.

Report has it that her husband is critically ill and her two children injured.

Of the 64 injured, 20 are in a critical condition, and some have lost limbs. Twelve of them are known to be children.