A British man who took four people hostage at a synagogue in Texas had been investigated by MI5.
Malik Faisal Akram, from Blackburn in Lancashire, was the subject of an investigation in late 2020 but by the time he flew to the US he was assessed to be no longer a risk, BBC reported.
Akram, 44, was shot dead by police.
He had been on the British security service's watchlist as a "subject of interest" in 2020 and was investigated in the second half of that year.
But by 2021 Akram, who had a criminal record in the UK, had moved from the active list to the former subject of interest list and was no longer considered a threat.
Two teenagers remain in custody after being arrested in England as part of the investigation into what US President Joe Biden described as "an act of terror", but their ages and genders have not been released.
The siege began at around 11:00 local time (16:00 GMT) on Saturday, when police were called to the Congregation Beth Israel synagogue.