Police are hoping to enlist the help of the Royal Air Force as the search for Alice Gross runs into it its fifth week.

This afternoon, speaking at near the last sighting of the 14-year-old along the towpath of the Grand Union Canal, detective superintendent Carl Mehta said he was hoping for searches from the air by the military and discussions were under way. He added more CCTV has been watched than after the London riots.

He said: "There is nothing to suggest that anyone was lying in wait on that Thursday (August 28).There is also no suggestion that any accomplices were involved."

Police were searching drains and scrub land with the aid of sniffer dogs this afternoon following a reconstruction of Alice's last known movements, while police cadets handed out flyers with Alice's picture to the public.

Police cadets hand out missing posters in the search for Alice Gross one month on

Mr Mehta appealed for witnesses, including the prime suspect Arnis Zalkalns, to come forward. It is believed the 41-year-old, of Castlebar Road, Ealing, may have fled to his native Latvia.

He said: "Arnis please come forward. I need to speak to you. And I'd like to also appeal to anyone who may be helping him by providing money or shelter to please come forward. The family are desperate. We need witnesses to come forward. Even people who can say they were in a part of Hanwell and didn't see Alice. This is still relevant.

"Alice had a very distinctive walk where she was swinging her arms and striding out, rather like power walking. It is her walk that has made it so easy to pick her out on poor CCTV. On the afternoon that she disappeared there was a short heavy rain shower. This hit just as she got to Trumpers Way bridge. We now know that three of the five cyclists we were trying to trace (who have come forward) did shelter under that bridge at around the same time as Alice. We know from her family that she loved the rain and is unlikely to have sheltered. We still need the two other cyclists to come forward."

Mr Mehta praised residents of the borough for their help and assured them and said: "In 30 years of doing this job I have never seen a community come together like this. And I would like to thank them for their ongoing help. The search is an ever expanding one. As we get more information the search widens.

"We have put out international alerts regarding Arnis to other countries. We are doing everything you would expect us to do to find him."

Click here for the timeline of events since Alice Gross went missing.