Police trying to trace missing schoolgirl Alice Gross have dredged a stretch of the canal where she was last seen on 28 August, 2014.
The 14-year-old was spotted on CCTV walking along the towpath of the Grand Union Canal in west London one month ago. Officers hoped searching the canal bed would uncover lost possessions, such as her iPhone, which could hold the key to her disappearance. However, no new leads have been discovered.
More than 300 officers are involved in the massive hunt for the teenager, in what has been called the largest search and rescue operation in the capital since the 7/7 bombings.
Police officers from more than twelve forces are now involved in the hunt and the RAF has been drafted in to help identify new search areas.
Speaking about the dredging of the canal, a Metropolitan Police spokesman said: "That search was conducted as part of the wider search and nothing of significance was found. Searches are ongoing."
The search has also included a reconstruction of Alice's last known movements which attracted 150 phone calls from members of the public with possible information.
But an area of disturbed earth at Elthorne Park in west London, which runs beside the canal towpath and was subject to a thorough investigation, was ruled out as no longer of interest.
Her mother, Rosalind Hodgkiss, said: "Every morning, as Alice's disappearance grows longer and longer, brings new agony, new anguish."
The Met has come under fire for delays in identifying convicted murdered Arnis Zalkalns as a risk. The Latvian, who is also missing, has been named as the prime suspect in the case of Alice's disappearance.