The 22 people who died in the Manchester Arena terror attack might still be alive if information had been handled differently, according to a review of the May slaughter released Tuesday.
The independent review, conducted by lawyer David Anderson and ordered by Home Secretary Amber Rudd, said the May 22 attack might have been thwarted "had the cards fallen differently."
Anderson's assessment was part of an official report into the way police and the security services in the United Kingdom handled intelligence before four terrorist attacks earlier this year in London and Manchester, Sky News reported.
Manchester suicide bomber Salman Abedi had twice been a "subject of interest" in MI5 investigations in the years before the Manchester bombing, but those investigations by the British spy service were later closed.
In the months before the attack, intelligence officials received new information about the 22-year-old's activities, but the "significance was not fully appreciated at the time."
Anderson didn't provide further details about what intelligence authorities received that put Abedi back on their radar.
A planned meeting by the U.K's domestic intelligence service was scheduled for May 31 to discuss whether Abedi should be further investigated, but it came too later.
The report by Anderson concluded "in retrospect, the intelligence can be seen to have been highly relevant to the planned attack."
Besides the Manchester attacker, Anderson's report also revealed two other terrorists involved in the Westminster and London Bridge attacks this year were on the radar of police and intelligence services.
Khalid Masood, who killed five people at Westminster Bridge in March, was previously investigated by authorities for extremist links and criminal activity. Authorities closed his case file five years before the attack and he was no longer deemed to be a subject of interest.
While the report detailed missed opportunities, it also credited police and MI5 with stopping many other attacks despite unprecedented extremist activity.
Anderson said 22 terrorist plots had been thwarted by the authorities in the past four years, with nine in the past year alone.