Manchester was remote controlled and made by professional ‘This isn’t something you knock up in your shed’

The bomb that killed 22 people in Manchester on Monday is the most sophisticated device set off in Britain since attacks by the IRA, it emerged today.

The explosive, which was packed in a Karrimor backpack and carried into the arena by Salman Abedi, was made by a professional and could have been triggered remotely, investigators believe.

Photos of bloodstained fragments from the device used in Monday night’s attack were leaked last night, shedding more light on how Abedi massacred Ariana Grande fans as they piled out of the UK’s biggest indoor venue.

The 22-year-old suicide bomber appeared to have used a powerful explosive in a metal container, packing bots and nails around it to inflict maximum injuries.

Experts who have analysed the pictures believe the bomb may have been detonated by somebody else – a technique used by terror groups to avoid suicide bombers losing their nerve when it comes to blowing themselves up.

 Suicide bomber Salman Abedi carried the explosive in a metal container, believed to have been in a Karrimor backpack

 Investigators found a destroyed 12-volt lead acid battery (pictured) after the attack in Manchester Arena, suggesting measures were taken to make sure the bomb didn’t fail. It is thought the bomb was made by a professional

 The bomb’s detonator. The sophistication of the device suggests it was probably not made by Abedi himself

Experts said it was the most sophisticated bomb seen in Britain since the Troubles in Northern Ireland and could have been set off remotely or by a small detonator held by Abedi.

Pictures of fragments of the device, first published by the New York Times, came just hours after the UK Government issued a warning to US authorities not to release details of the terror investigation.

The leaked photos show the remains of a small handheld detonator used to explode the bomb, which contained nails, nuts and bolts.

READ MORE Source: Manchester was remote controlled and made by professional | Daily Mail Online