The last is yet to be heard in last Friday’s terror attack on a Tube train following the arrest of a 17-year-old boy by police in south London.
The teenager was nabbed and detained after officers executed a warrant in Thornton Heath at around midnight on Thursday.
The total number of arrests in the investigation has risen to six, with the latest arrest.
It would be recalled that a homemade bomb popularly known as Improvised Explosive Device (IED), partially exploded on a rush hour District Line train at Parsons Green, injuring 30 people.
Police have begun a search of the property where the teenager was arrested under Section 41 of the Terrorism Act.
Commander Dean Haydon, head of Scotland Yard’s 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 now have six males in custody and searches are continuing at five addresses.
“Detectives are carrying out extensive inquiries to determine the full facts behind the attack.”
Further searches are continuing at two addresses in Surrey and are expected to last some days, the police said.
Read more: BBC