A British-born man who was once investigated for connections to violent extremism carried out the deadly attack outside Parliament in London on Wednesday, according to Prime Minister Theresa May.
Addressing lawmakers in Parliament who only a day earlier had been under lockdown, Mrs. May said on Thursday morning that the attacker was “a peripheral figure” who had been examined by MI5, Britain’s domestic counterintelligence agency, but who had not been “part of the current intelligence picture.”
Mrs. May said that officials were not ready to release the man’s name, but she added that “there was no prior evidence of his intent or of the plot” and that “our working assumption is that the attacker was inspired by Islamist ideology.”
The authorities raided six properties across the country on Thursday, detaining eight people in London and in Birmingham, in central England, as they pressed ahead with a fast-moving investigation.
The authorities emphasized that they believed the assailant had acted alone and that they did not expect any further attacks; Mrs. May said that the nation’s threat level would remain “severe,” meaning that an attack was likely, and not raised to “critical,” signaling an imminent attack.
