A week after over 20 properties were raided in connection with last Thursday's alleged plot to blow-up transatlantic flights, police continue their search of homes in London, High Wycombe and Birmingham.
The majority of the properties still being searched are in east London, while five are being investigated in High Wycombe and one in Birmingham.
Police continue to search 11 properties in east London, eight in Walthamstow, including two houses on Albert Road and a flat at 386 Forest Road.
Eyewitness John Weir, who lives opposite a terraced house containing a number of flats in Forest Road, said about 20 officers had forced its front door open at about 2350 BST last Wednesday during the original raid.
Officers had searched a first floor flat by torchlight but no-one appeared to have been taken out of the property, Mr Weir added.
Police officers were continuing to search two houses in Albert Road, Walthamstow.
One man, a father of someone who lives close by, said he believed the couple living at one of the houses were foster parents.
He said: "I'm sure they used to foster children. They had five of their own, all girls I think, and then there were always little ones which they fostered."
Nearby, a second house at 5a Folkestone Road continues to be monitored, after being raided last Wednesday.
Other properties being searched in the area include 68 Banbury Road, where Abdula Ahmed Ali lived with his wife Cossor, 30 Ravenswood Road and 104 Queen's Road.
Elsewhere in east London, homes at 14 Nottingham Road in Leyton and 7 Priory Road in Barking, are still being searched.
One house at 243 St Margarets Road in the Ward End area of Birmingham continues to be examined.
June Lethbridge, 85, who lives beside, said a family had lived there for 12 years.
Earlier in the investigation, properties at nearby Bordesley Green and Belchers Lane had been searched.
On Thursday 17 August, a police source said a suitcase carrying "everything you would need to make an improvised device" had been found in King's Wood - woodland in High Wycombe.
And on Wednesday "items of interest" were said to have been found in the wood.
Five addresses in High Wycombe continue to be searched, including a Victorian semi at 41 Micklefield Road and a home at nearby 36 Walton Drive.
The other properties being investigated are 31 Hepplewhite Close, 82 Chairborough Road and 32 Plomer Green Avenue.
Paul Goodman, the Conservative MP for High Wycombe, said the events highlighted two key points.
"First, that the vast majority of Muslims in High Wycombe and elsewhere are peaceful and law-abiding citizens - and that any hostile action towards them is reprehensible.
"Second, that all Muslims must strive ceaselessly to condemn, confront and root out support for terror from their communities."