The second of six men to have been arrested over the Parsons Green attack Friday has been released without charge.

Described as ‘Man B’ by Metropolitan Police and identified in some media reports as Syrian origin Yahyah Farouk, the 21-year-old was released Thursday afternoon with no further action taken.

The man had been arrested in Hounslow, London on Saturday evening and was the subject of a special warrant issued by Westminster magistrate’s court to extend the time available to officers to question him.

Another five men held in connection to the bombing — which failed to explode properly but still injured 30 directly and indirectly — remain at a south London police station. The force said in a press release further special warrants had been issued to extend the questioning time of two men had been secured Thursday.

Sixth Arrest Made By London Police in Parsons Green Bomb Investigation — Arrests Made At ‘Refugee Housing’ https://t.co/T32wvL2xb6 — Breitbart London (@BreitbartLondon) September 21, 2017

While few details have been made public about the held men, it is understood the 18-year-old prime suspect is of Iraqi origin and may have been referred to a government deradicalisation programme before the attack. Two more of the arrested men are understood to have been taken into custody from a refugee home in the south of Wales this week.

Commander Dean Haydon, head of the Met Counter Terrorism Command, said: “This continues to be a fast-moving investigation. A significant amount of activity has taken place since the attack on Friday.

“We have five males in custody and searches are continuing at four addresses. Detectives are carrying out extensive inquiries to determine the full facts behind the attack.”

“We are asking the public to look out for anything that seems out of place, unusual or just doesn’t seem to fit in with day-to-day life. It may be nothing, but if you see or hear anything that could be terrorist-related, trust your instincts, then act, and call us.”