Terror suspect Mohamed Amoudi, arrested in raids on Thursday, is claimed to have previously been released without charge after being accused of taking two teenage boys to join Islamic State in Syria. Amoudi is believed to have taken the teens out of the country after attending a talk given by Moazzam Begg’s CAGE organisation hosted by an Islamic society at Queen Mary, University of London.

Amoudi, 21, who is reportedly a teacher with a master’s degree in physics, is considered a key suspect in an Islamist bomb plot. He was one of six people arrested in raids conducted by armed counterterror police in London and Kent.

The Times reports that Amoudi is a British citizen born in Yemen. In 2015, Amoudi took two 17-year-old boys from the Wembly area to Turkey. Turkish authorities suspected they were heading for the border with Syria, and were stopped and sent back to Britain. He was detained by British police, but was never charged.

Amoudi and the teenagers made the trip days after the suspect attended talks organised by human rights group CAGE, which represents former Guantanamo Bay inmates. The event was hosted by an Islamic society at Queen Mary, University of London, where Amoudi was studying. CAGE had described Islamic State executioner “Jihadi John”, Mohamed Emwazi, as a “beautiful young man”.

The event was addressed by Haitham al-Haddad, who has called for apostates from Islam to be stoned to death. Begg, a director of CAGE, also spoke at the event where he told students that Muslims were “feared and hated”.

Begg served as an inmate in Guantanamo Bay, where he signed a confession stating that he was an Al Qaeda recruiter. After his release, negotiated by the Blair government, he returned to the UK and retracted those statements, but admitted being at Islamic training camps.

Amoudi was part of a group called Strivin Muslims, through which it is believed he met the schoolboys.

One source told The Times that the alleged plotters were “rapidly moving towards putting their plan into action”. It is believed their intended target was in central London.

During the operation on Thursday, Amoudi is understood to have fled undercover officers who followed him on a bus to a busy high street in north-west London. Counterterrorism police eventually arrested him outside Willesden Green library on suspicion of involvement in the “active plot”.