Manchester bomber Salman Abedi learned how to make explosive device from YouTube videos

The terrorist downloaded a range of online material, including from the dark web

CCTV image of Manchester bomber Salman Abedi (PA/GMP)

Salman Abedi reportedly learned how to make the bomb he used to kill 22 people in the Manchester attack from YouTube tutorial videos.

The origin of the device used by the suicide bomber has been a key line of investigation for authorities. Haras Rafiq, CEO of the Quilliam counter-extremism group, previously told The Independent authorities were trying to understand whether the suicide bomber learned how to make the bomb online, in Libya or in the UK.

According to The Times, Abedi used the video platform to learn about the manufacture of improvised devices, and downloaded material from other websites about the chemical compound used in the bomb.

A source with knowledge of the police investigation told the newspaper the information about how to construct devices using TATP - the same homemade explosives used by Isis in the Paris and Brussels attacks - was accessed on a range of online sources, including the dark web.

Following the attack, a 22-minute video on YouTube and Facebook from a series called “Jihadi Ideas for Lone Lions” told viewers how to make a household bomb from the same type of explosive used by Abedi.

The video showed someone making a bomb using easily obtained household items. The video has now been taken down.

Abedi is believed to have used at least three properties, including in Blackley, his former home in Fallowfield and another flat in Granby Row, central Manchester, to prepare the bomb.

Officers also fear Abedi may have made a second bomb after raids on his home discovered a stash of chemical explosives, which is believed to have been enough to “build two or three bombs”.

Police previously suggested Abedi may have built the bomb in under four days after flying back from Libya on 18 May. Experts also confirmed terror training would have enabled Abedi to build the explosive in 24 hours after it was reported the 22-year-old met with Isis-linked militants in Libya.

Even if Abedi, a university dropout, may have received real-life training, reports that he managed to build the bomb after viewing online tutorials will continue to raise questions over the accessibility of such material on mainstream web platforms.

A YouTube spokesman said: “We do not allow bomb-making videos and quickly remove flagged videos that break our rules. We employ thousands of people to counter abuse of our platform and are working with government, law enforcement and civil society groups to tackle the problem of violent extremism online.”

Facebook has launched its Online Civil Courage Initiative in order to tackle online extremism. The UK Government has accused technology companies of providing “safe spaces” online for terrorists.

Mark Zuckerberg's social media giant has now partnered with the Jo Cox Foundation, Community Security Trust, Tell MAMA, Imams Online and the Institute for Strategic Dialogue to keep content related to terrorism off the site.

“No one should have to live in fear of terrorism – and we all have a part to play in stopping violent extremism from spreading,” said Sheryl Sandberg, Facebook´s Chief Operating Officer.