A forensic search of Tia Sharp's grandmother's house has begun, a week since the schoolgirl went missing.
The 12-year-old was last seen at the terraced property on the New Addington estate near Croydon, south London, seven days ago.
A cordon was placed around the house on The Lindens where Christine Sharp, 46, lives with her partner Stuart Hazell, 37.
More than 20 officers from Scotland Yard arrived at the house on Friday afternoon and white-suited forensics officers were later seen going inside the property.
Detective Chief Inspector Nick Scola, who is leading the investigation, said officers were carrying out a "pre-arranged search" which was likely to take at least one or two days.
The police cordon prevented anyone from getting within about 100 yards of Mrs Sharp's house. She was driven away from the estate by police officers. A search dog had spent 30 minutes inside the property this morning, and bags of evidence were removed by officers.
Mrs Sharp broke down as she spoke about Tia's disappearance.
She said: "My only message to Tia is that I love her. She is my life. I don't know where she has gone. I don't know how she's gone. She's not staying away by choice, I know this. I just don't know what else to say."
Mrs Sharp added: "We will help the police and anybody and everybody else in every way I can, so will every member of my family. We are going to cause them no obstruction whatsoever. Whatever they want to do they can do it, no problem. I just want my baby back."
Phillip Wheatley, Tia's headteacher at Raynes Park High School in Merton, has described her as a friendly young person who is well-liked by staff and students and enjoyed a successful first year at the school.