Alice Gross: Police search National Trust estate for missing schoolgirl

More than 300 officers from a dozen police forces are involved in the hunt

Police officers search an area next to the river Brent for clues in the hunt for schoolgirl Alice Gross in London (Peter Macdiarmid/Getty Images)

Police searching for missing schoolgirl Alice Gross have moved part of their hunt to a National Trust-owned estate near to where the teenager was last seen.

Officers from Scotland Yard have for the first time been combing Osterley Park, a Georgian country house and estate in west London, roughly two miles from the 14-year-old's last sighting near the Grand Union Canal.

It has been exactly a month since Alice failed to return home to her family, leading to the Metropolitan Police's biggest search operation since the 7/7 bombings.

More than 300 officers from a dozen police forces across the country are involved in the search, while the RAF has also assisted to help identify possible new search sites.

A stretch of the Grand Union Canal, which Alice walked alongside before she disappeared, has also been sifted through in the hope to recover her possessions, although officers, again, drew a blank.

Alice was last seen on CCTV walking along the towpath by the canal as it passes under Trumpers Way at 4.26pm on August 28.

Detectives are searching through hours of "crucial" footage from hundreds of CCTV cameras to try and piece together her last movements.

Latvian Arnis Zalkalns is the prime suspect in the investigation into missing teenager Alice Gross (PA)

Searches are also continuing to take place through scrubland running alongside the canal

Police are hunting for prime suspect Arnis Zalkalns, a convicted murderer from Latvia, who was filmed cycling the same route behind the teenager.

Officers are working with authorities in Latvia in a bid to trace the labourer, who was reported missing in the days following Alice's disappearance.

Her mother, Rosalind Hodgkiss, said: "Every morning, as Alice's disappearance grows longer and longer, brings new agony, new anguish."

Police have come under fire for delays in identifying Zalkalns as a risk, and Commander Graham McNulty has admitted 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 have come under fire for apparently holding no record of his conviction for bludgeoning and stabbing his wife Rudite to death in Latvia.

He is described as white, 5ft 10in and stocky, with dark brown hair that he normally wears tied in a ponytail.