Details are emerging about Manchester bomber Salman Abedi, but questions remain around his ties to global jihadism and route to radicalisation.

At least 22 people were killed, including children, and dozens wounded on Monday night when an attacker set off an improvised explosive device (IED) at the Manchester Evening News Arena. ISIS claimed responsibility on Tuesday, saying the blast was perpetrated by a "soldier of the caliphate." The jihadi group described the concert goers as "Crusaders" and "mushrikin," or idolatrous, while describing the concert arena as "shameless." Even before the claim, ISIS supporters celebrated the attack online. 

The male bomber, who also died in the blast, entered the arena foyer when an Ariana Grande concert was coming to a close and detonated, according to police. A source inside the venue suggested the explosives may have been packed with metal and bolts. Police identified the attacker on Tuesday evening as Salman Abedi, 22, a local resident whose parents had emigrated from Libya. A total of eight other people were arrested around Manchester in connection to the incident, and the attacker's brother and father, who Libyan officials say were aware of the plot, were arrested in Tripoli. It was the worst terror attack Britain has seen since the July 2005 attacks in London.

Police are gathering evidence on whether the assailant was acting alone, or was part of a wider network. According to a US intelligence official, Abedi had "clear ties to al-Qaeda" and had received terror training abroad. The official claimed the 22-year-old's bomb was "big and sophisticated" and used material hard to obtain in the UK, making it "almost impossible to see he didn't have help." According to one report, Abd al-Baset Azzouz, an expert bombmaker who has been accused of running an al-Qaeda network in eastern Libya, lived close to Abedi in the UK. Azzouz was among a group of Gaddafi dissidents, who were members of the outlawed Libyan Islamic Fighting Group, living in the area.

Before the ISIS claim, ISIS supporters on social media were lauding the incident, which took place on the fourth anniversary of the murder of British soldier Lee Rigby in London. According to terrorism researcher Rita Katz, some encouraged others to carry out similar attacks elsewhere in the UK. Other messages from Twitter accounts affiliated with ISIS claimed the bombing was a response to airstrikes over Iraq and Syria, a similar message to the ISIS-claimed London attack on The Palaces of Westminster and other recent assaults in Europe.

As investigations continue there are pressing questions around his jihadi ties. It is likely that he received material and logistical support in preparing for the attack. Abedi is believed to have travelled to Syria and became radicalised before returning to the UK. Days before the attack he also reportedly returned from a trip to Libya. According to yet another report, he had recently spent time in Germany. 

Attacks on entertainment venues have happened before. When ISIS claimed the November 2015 attack on Paris’ Bataclan theatre in 2015, it said it was hosting a “concert of prostitution and vice.” Although the attack in Manchester was not the first targeting such a venue in Europe, it is the first which targeted such a young audience. Many of those wounded in the foyer of the arena were parents waiting to pick up their children. Online, ISIS supporters have claimed the attack was a response to the bombing of children in Mosul. 

Last November, ISIS officially released detailed instructions on how to make a homemade bomb, which was followed by guidelines on “hunting your prey” in the UK, and encouragement on using tactics which require little expertise. ISIS’ official magazine, Rumiyah, has instructed readers to carry out lone attacks on the West, with directives on new tactics for carrying them out.

This month, an al-Qaeda propaganda video featuring Osama bin Laden's son Hamza centered around "advice for martyrdom-seekers in the West," in which he urged extremists to carry out attacks in the West. Although ISIS has taken responsibility for recent terrorist attacks in Western countries, it is important not to discount the global appeal that al-Qaeda maintains.

The group has been involved in a number of attacks in the West since 9/11, including the Madrid bombings in 2003, the London bombings in 2005, the Boston Marathon bombing in 2013, and most recently the attack on the offices of Charlie Hebdo in Paris in 2015. Long before the emergence of ISIS, al-Qaeda has been promoting the concept of 'Open Source Jihad,' encouraging attacks against the West, providing online how-to guides.

Recent ISIS-claimed attacks in London, Berlin, and Nice, have been low-tech, using vehicles and knives, tactics that evade authorities and allow militants who are unable to plan larger attacks to participate in terrorism. Access to instructions on constructing, storing, and deploying IEDs is easily accessible via a Google search, as research by the Centre on Religion & Geopolitics into extremist content online has found.  

Theresa May raised the UK terror threat to "severe" in August 2014 and following the naming of the suspect in the Manchester attack, increased it to "critical," the highest level. The Director General of MI5, Andrew Parker, has said that there would be successful attacks in the UK at some stage, and more recently the top counter-terror official at the EU claimed that attackers would be more dangerous as an exodus of increasingly seasoned fighters return from the failing ISIS operations in the Middle East. The extremist threat throughout Europe is still severe. Between March and December 2016 there were at least 320 extremist arrests in 16 countries throughout the continent.