Scene of London attack
Scene of London attackReuters

British police said on Monday they had found no evidence that Khalid Masood, the terrorist who killed four people in an attack on parliament last week, had any association with the Islamic State (ISIS) or Al-Qaeda, Reuters reports.

At the same time, they noted that Masood was clearly interested in jihad. The comments come despite the fact that ISIS claimed responsibility for the attack, saying Masood was one of its “soldiers”.

Masood drove a car through a crowd of pedestrians on Westminster Bridge, killing three and injuring about 50, then ran through the gates of parliament and fatally stabbed a police officer before he was shot dead.

Neil Basu, senior national coordinator for UK counter-terrorism policing, said on Monday there was no evidence that Masood had been radicalized in prison in 2003 and it was pure speculation to suggest that had happened.

Masood, 52, was British-born and had several previous convictions for offences such as grievous bodily harm, possession of a knife and disturbing public order. He had not been convicted of any terrorism offense.

"His attack method appears to be based on low sophistication, low tech, low cost techniques copied from other attacks, and echo the rhetoric of IS leaders in terms of methodology and attacking police and civilians, but at this stage I have no evidence he discussed this with others," Basu said in a statement, according to Reuters.

"I know when, where and how Masood committed his atrocities, but now I need to know why," he added, appealing to anyone who may have been in contact with him on the day of the attack to come forward.

Police said on Saturday that Masood acted alone, though they are trying to pinpoint his motive and identify any possible accomplices.

As part of those efforts, authorities are trying to gain access to Masood’s final communications sent via WhatsApp, which are encrypted.

British Interior Minister Amber Rudd on Sunday called on technology companies such as WhatsApp to cooperate more with law enforcement agencies and stop providing "a secret place for terrorists to communicate" using encrypted messages.