Devon, Cornwall and Somerset Police officers have joined in the search for missing teenager Alice Gross who has now been missing for five weeks.
The Metropolitan Police thanked the Westcountry force and said the capital's officers are grateful for the specialist resources and support they have received from forces across Britain.
Police will continue to scour hours of footage from hundreds of CCTV cameras for clues as Scotland Yard confirmed the RAF had been drafted in to help in their search for the missing girl who vanished near her home in west London.
An ongoing search of scrubland along the towpath near the Grand Union Canal in west London where the 14-year-old was last seen will resume today, and police said CCTV is playing a "crucial role" in piecing together the last known movements of Alice, who has now been missing for five weeks.
And, along with more than a dozen police forces across the country, the RAF have also provided support with "aerial analysis" pinpointing places to focus the hunt.
Thirty detectives are painstakingly reviewing 35 terabytes of material from around 300 CCTV cameras covering a six-mile-square area.
Yellow ribbons can be spotted tied to railings and front doors in west London in a bid to jog people's memory to help the search for the missing schoolgirl.
Runners taking part in the Ealing Half Marathon have also said they will wear the ribbons as they complete the route today.
A Metropolitan Police spokesman said: "We can confirm that as part of the search operation, the RAF has provided assistance in the form of aerial analysis to identify potential areas of interest to officers.
"This continues to be a massive investigation.
"A range of officers and staff from across the Met are taking part in the ever-expanding search for Alice.
"To date the search has involved the Met's underwater and confined space search team, marine support unit, search dogs, air support unit, Territorial Support Group, local borough officers, volunteer police cadets, visual images identification and detections officers, plus licensed search officers."
Alice was captured on CCTV walking along the towpath next to the canal as it passes under Trumpers Way at 4.26pm on August 28 but has not been seen since.
She could have taken one of several paths leading back towards her home in Hanwell.
Speaking yesterday, Detective Superintendent Carl Mehta said: "CCTV is clearly crucial in our investigation, but we still need the public's help and I want to hear from anyone who saw Alice during the afternoon of the Thursday she was last seen.
"Our searches are continuing in the local area today, and there are extra officers involved. I'd like to thank the community who have been so supportive and patient.
"In over 30 years of policing I have never seen such a strong community reaction. This is a community that is totally behind the search to find Alice and bring her home."
Convicted murderer Arnis Zalkalns, the prime suspect in her disappearance, who has also vanished, was filmed cycling the same route behind the teenager.
During the fresh appeals, Mr Mehta stressed that the Latvian, who was also accused of molesting a 14-year-old girl in 2009, was just "one line of inquiry".
Police received 150 phone calls after staging a reconstruction of Alice's last known movements.
Investigators said an area of disturbed earth at Elthorne Park in west London, which runs beside the canal towpath, was no longer of interest.
The latest development in the increasingly desperate hunt for the teenager came after her parents and police renewed appeals for information yesterday, four weeks since she was last seen.
Her mother, Rosalind Hodgkiss, said: "Every morning, as Alice's disappearance grows longer and longer, brings new agony, new anguish."
The force has come under fire for delays in identifying Zalkalns as a risk, and Commander Graham McNulty admitted that British detectives would have no power to arrest him if he has fled abroad.
The general labourer, who worked at a building site in Isleworth, west London, is thought to have come to the UK in 2007, but authorities here apparently had no record of his conviction for bludgeoning and stabbing his wife Rudite to death in his native country.
He is described as white, 5ft 10in and of stocky build, with dark brown hair that he normally wears tied in a ponytail.
The Metropolitan Police said they were grateful for the support they had received from forces across country including Devon and Cornwall Police, Surrey Police, Sussex Police, Avon and Somerset Police, the National Crime Agency, British Transport Police, Dyfed Powys Police, South Wales Police, Thames Valley Police, Hampshire Constabulary, Gloucestershire Constabulary, West Yorkshire Police, Bedfordshire/Hertfordshire/Cambridgeshire, Norfolk/Suffolk, Nottinghamshire Police and Lincolnshire.
