It is believed the man behind the terror attacks in Westminster was investigated by MI5 about a plan to blow up an Army Base.
Adrian Ajao, who changed his name to Khalid Masood after converting to Islam, killed four people including a police officer last week in Westminster.
Theresa May confirmed that Ajao had been investigated by the security services for links to "violent extremism".
However, it was decided that he did not pose a terror threat.
Ajao moved to Luton in 2009 after living in Saudi Arabia.
According to The Daily Telegraph, while living in Luton it is thought he met the gang who were planning the Army Base attack at the local gym.
In 2010 the MI5 started monitoring the gang of four extremists after learning they were planning an attack.
They managed to bug the men's car and, the paper reports, that is how they learnt of the plan to drive a toy car carrying explosives under the gates of the town's Territorial Army Base.
Zahid Iqbal, Mohammed Sharfaraz Ahmed, Syed Hussain and Umar Arshad, admitted to plotting to launch a bomb attack on a Territorial Army base in their hometown of Luton. They were jailed for 44 years.
The report also suggest the gang discussed plans to attack MI5 headquarters, a US Air Force base, an English Defence League gathering and a local shopping centre.