March 27 (UPI) -- The Metropolitan Police Service said Monday it has found "no evidence" the suspect in the attack in Westminster last week was linked to the Islamic State or al-Qaida.
Khalid Masood, a 52-year-old British-born citizen, killed four people and injured dozens others outside Westminster Palace in central London on Wednesday. He drove a car into pedestrians, then fatally stabbed a police officer before he was shot dead.
Neil Basu, senior national coordinator for British counter-terrorism policing, said in an update it was "pure speculation" Masood was radicalized in prison in 2003.
"Whilst I have found no evidence of an association with [the Islamic State or al-Qaida], there is clearly an interest in jihad," he said.
His first criminal conviction was in 1983 for criminal damage and his most recent was in 2003 for possession of a knife, police said.
Authorities said Masood was never convicted of terror crimes.
"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," Bau said.
Police said Masood sent an encrypted message moments before the attack using the WhatsApp social media messaging app.
"There has been much speculation about who Masood was in contact with immediately prior to the attack," Basu said. "All I will say on this point is that Masood's communications that day are a main line of inquiry."
At birth, his name was registered as Adrian Elms and then he took his stepfather's last name of Ajao. He changed his name to Khalid Masood in 2005.
"I know when, where and how Masood committed his atrocities, but now I need to know why," Bau said. "Most importantly, so do the victims and families."
Two people from Birmingham were being held on suspicion of preparing terrorist acts after nine were released without charges, the BBC reported.
Thirteen people were still hospitalized Monday, the BBC reported.