British police said on Monday they had found no evidence that Khalid Masood, who killed four people in an attack on Britain’s parliament last week, had any association with Islamic State or al Qaeda.

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

“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.