Arnis Zalkans, 41, disappeared from his home in Ealing on 3rd September - just one week after 14-year-old Alice Gross vanished while walking along a canal in West London.

He has now been identified in CCTV footage, which shows him cycling along Brentford Lock at 4pm - just 15 minutes after the schoolgirl waked along the same route.

Police have said that he is likely to have come across Alice as they were both going in the same direction, north along the canal towpath.

WATCH THE CCTV FOOTAGE BELOW:

Zalkalns has not accessed his bank account or used his mobile phone since September 3, and has not returned home since this date.

Detective Superintendent Carl Mehta, from the Homicide and Major Crime Command, said today: “I want the public’s help. On Thursday 28 August Arnis Zalkalns left work, in Isleworth, at about 3.30pm on his bike. Did you see him that afternoon? Either on his own, or with a teenage girl?

“I also need to hear from anyone who knew Arnis whom we have not yet spoken to. His family and work colleagues have stated he was behaving normally in both the days before and after Alice’s disappearance. They are deeply concerned about his disappearance.

“Three weeks ago today Alice left home as usual. She has not been seen since 4.26pm, when she walked along Trumpers Way. So far the public have given us great support, but there may still be people out there who were walking in the area Alice was on that Thursday who have not yet spoken to us.

"If you were and you saw anything that could help progress our investigation - please call."

He also confirmed that Arnis Zalkans served a seven-year prison term for murder in Latvia in the 1990s, and was also arrested in the Ealing area in 2009 for indecently assaulting a 14-year-old girl.

It is thought Zalkalns has been in the UK since 2007 - however, he left his passport at home in Ealing when he went missing two weeks ago.

Police have warned the man "clearly poses a risk to the public". Any one who sees him is asked not to approach him.

A reward of £20,000 is being offered to anyone who has information that leads detectives to find the teenager, who was last seen walking along the Grand Union Canal in west London.

Alice, who is from Hanwell, Ealing, left her home at 1pm on 28 August telling her parents that she would return later that night.

A rucksack containing some of her belongings was found alongside the towpath on 2 September, while an amnesty has been offered on the teenager’s missing iPhone as officers believe it could contain clues to her whereabouts.

She texted her father at 3pm to ask when he would be home as she did not have any keys to the house, showing an intention to return.

Alice is described as being white, 5ft 2in tall and of slim build with shoulder-length, light brown hair. She was wearing dark blue jeans and a grey top, and tartan-framed glasses.

Scotland Yard has released an interactive map of the route Alice took, as part of their #FindAlice investigation.

Anyone with information should call 020 8358 0100, or call Crimestoppers anonymously on 0800 555 111.