Police said they had 80 officers trying to find missing Tia Sharp, as they revealed they had diverted Olympic resources to search for the 12-year-old.
Met police Commander Neil Basu told a press conference there had been 60 possible sights of Tia so far.
"We are doing everything we can to try to find her and trying to support the family," he told journalists.
Tia Sharp has been missing for five days
"I can't imagine how it must feel for this family after five days."
Earlier police took a German Shepherd dog into the south-east London house where it is believed she was last seen.
The police dog was taken into the terraced property at the Lindens, New Addington, by a dog handler shortly after the family were given an inquiry update by Detective Chief Inspector Nick Scola.
Tia was last seen leaving her grandmother's house on Friday
The officer emerged from the house, where the schoolgirl's grandmother Christine Sharp, 46, lives with her partner Stuart Hazell, 37, and told reporters: "This morning I have been in to see the family and update them with details of the investigation.
"Of those details there is nothing I can share with you at the moment."
It was thought the last person to see the 12-year-old was her grandmother's partner Stuart Hazell, to whom she shouted she would be "back by six". He was today seen being led from Mrs Sharp's house by two men in plain clothes, and was put into a car and driven away. Police said a man in his 30s was being interviewed as a witness but has not been arrested.
Tia, who has never gone missing before, seemingly vanished without a trace on Friday afternoon after telling relatives she was going to the Whitgift Centre in Croydon town centre.
