MANCHESTER, England—Britain’s MI5 security service has launched an internal investigation into how it handled intelligence about Manchester suicide bomber Salman Abedi, who killed 22 people in an attack outside a pop concert last week, a U.K. security official said Monday.
Abedi, a 22-year-old British-born son of Libyan immigrants, had been reported to the authorities for espousing extremist sentiments, saw combat as a teenager in Libya’s civil war and lived in a neighborhood that has produced recruiters and fighters for Islamic State.
Last week, Abedi, dressed in a puffy Hollister winter jacket, bluejeans and a gray baseball cap, walked into a crowd of concertgoers streaming out of a performance by American pop star Ariana Grande and detonated a shrapnel-filled explosive device in the deadliest terror attack in Britain since 2005.
British officials have said Abedi was “known” to security services. He was one of 20,000 suspected extremists MI5 has tracked in the past, but wasn’t among 3,000 under active investigation by the agency at the time of the bombing, the official said.
“He was part of an investigation that was closed, when it was decided it was not necessary or proportionate to continue it,” the official said. “We’re reviewing things in the sense that we’re looking back and want to learn lessons.”
Police on Monday were holding 14 people—including Abedi’s older brother and two cousins—as they tried to piece together what authorities have described as a possible “network” of accomplices that helped him prepare for and carry out the attack.
Abedi’s father and younger brother, Hashem, were in the custody of a Libyan militia in Tripoli.
Authorities worried Abedi had manufactured bomb materials that weren’t used in last week’s attack. But after days of searches and arrests around Manchester, the security services believed they had tracked down all of the hydrogen-peroxide-based explosives linked to Abedi, the official said.
Manchester police on Monday published a photograph of Abedi carrying a blue suitcase and appealed to members of the public for any information about the bag. The police said there was no reason to believe the suitcase or its contents were dangerous, but advised caution.
Friends and acquaintances of Abedi say he had become increasingly religious and expressed interest in extremist groups in recent years.
In 2011, Abedi fought alongside his father as Libyan rebels sought to oust dictator Moammar Gadhafi. Many from Manchester’s Libyan community did the same. Abedi and other teenagers returned from the battlefield hardened, friends and community leaders said.
In the years that followed a number of young people from south Manchester left to fight with Islamic State in Syria and Iraq. CONTINUE AT SITE