UPDATED The so-called Islamic State group has claimed that the attacker who struck in the heart of London was a “soldier of the Islamic State,” according to the extremist organization’s Aaamaq news agency. The British-born assailant, recently identified as Khalid Masood, killed three people close to the British Parliament on Wednesday before being shot dead by police. Forty more were injured.

Police have revealed that 52-year-old Masood had been convicted of a range of crimes, including grievous bodily harm, possession of offensive weapons, and public order offenses. He had not been convicted of any terrorism offenses. Masood was born in Kent, in the South-East of England, and was believed to have been living in the West Midlands, a region in the center of the country, where he rented the car used in the attack.

Prime Minister Theresa May told lawmakers in Parliament on Thursday that Masood — who at that point had not been named — had been investigated by domestic intelligence agency MI5 in relation to concerns about violent extremism.

“He was a peripheral figure,” she said. “The case is historic. He was not part of the current intelligence picture. There was no prior intelligence of his intent or of the plot.”

May said he “acted alone” and that imminent further attacks were not expected.

Police have arrested eight people in connection with the attack, following raids in London and Birmingham.

Mark Rowley, Metropolitan Police’s acting deputy commissioner, said on Thursday: “It is still our belief — which continues to be borne out by our investigation — that [Masood] acted alone and was inspired by international terrorism.

“To be explicit, at this stage we have no specific information about further threats to the public.”

Masood drove a car through crowds on Westminster Bridge, which sits in the shadow of Big Ben, and then knifed a police officer who later died of his wounds.

One of those killed has been identified as Kurt W. Cochran, an American tourist who was in Europe with his wife celebrating their 25th wedding anniversary. His wife, Melissa, suffered serious injuries, a statement from the family said.