METROPOLITAN Police Commissioner Sir Bernard Hogan-Howe has defended the force's much-criticised search for missing schoolgirl Alice Gross, saying officers could not have worked harder.

Scotland Yard has come under fire for delays in finding the 14-year-old's body and that of prime suspect Arnis Zalkalns.

Around 600 officers, including search experts from the National Crime Agency and other forces, were involved in the operation - the biggest police search effort since the July 7 bombings in 2005.

But it took police more than a month to find Alice's body in the River Brent last Tuesday before Zalkalns's was discovered hanging from a tree in Boston Manor Park, west London, on Saturday.

Sir Bernard announced that the case was under review, but added that he was "not sure what more we could have done".

Speaking to BBC London Radio, he said: "No one wants to walk away not having found her. We wanted to find her and the person we regarded as a suspect.

"We worked incredibly hard and we had searched a park where he was eventually found.

"But the area where he was found had been marked for further search because it was really difficult to get into.

"This was not a case of a person hanging in a tree to be seen from 100 metres away, this was an enclosed area.

"Of course we all want reassurance that we did it as well as we could, that we did it efficiently and effectively. We are in the process of reviewing that and at the end of it we will be in a better position whether we could have done it differently.

"I'm not sure what more we could have done but we would have loved to have found them both quicker."

Alice, 14, from Hanwell, west London, went missing on August 28. Zalkalns, a convicted killer, who was spotted cycling behind Alice, went missing six days later.