Search dogs involved in the Madeleine McCann investigation have been recruited to help find missing Alice Gross.
Two springer spaniels are involved in the search effort for the 14-year-old schoolgirl who vanished more than a month ago.
The canines, named Tito and Muzzy, were previously used to sniff for clues on scrubland close to where Madeleine McCann vanished in the Portugese Algarve in 2007.
Although their efforts failed to uncover anything significant in the McCann hunt, they could be important in the search for Gross.
"South Wales Police is supporting the Metropolitan Police investigation into missing teenager Alice Gross. The mutual aid provision consists of several members of the Specialist Search and Recovery Team," the forces said in a statement.
Gross was last seen near the Grand Union Canal in west London on 28 August, 2014.
Latvian Arnis Zalkalns, a previously convicted murderer, is prime suspect in the investigation and has not been seen since being spotted in the same area as Gross on the day she vanished.