Arnis Zalkans has been suspected in the murder of a teenage girl in the UK (photo: Met Police)
British detectives have revealed that a Latvian builder they are searching for in connection with the disappearance of U.K schoolgirl Alice Gross is a convicted murderer.
Officers are now treating 41-year-old Arnis Zalkalns as a suspect in the disappearance of missing teenager Alice Gross.
Zalkalns was handed a seven year sentence for murder by a Latvian court when he was in his late twenties, the Daily Telegraph reports.
The builder, who lives with his partner and child in London, has not been seen since September 3 when he failed to turn up for work. Latvian police do not believe he has returned to his native country.
His disappearance came a week after 14-year-old Alice went missing after going for a walk close to the Grand Union Canal in west London.
Investigators said Zalkalns was seen on CCTV cycling along the Brentford lock 15 minutes after Alice had walked the same route on the day she went missing.
Detective Superintendent Carl Mehta, of Scotland Yard's homicide and major crime command, said the Latvian had been convicted of murder in his country. He was also arrested on suspicion of indecent assault in the Ealing area in 2009.
However Latvian authorities have insisted they were under no obligation to forewarn their British colleagues about Zalkalns conviction.
"According to law, we don't have to inform about previous convictions. We didn't get a request back then whether he was convicted. Once we got a request, we answered," said one Latvian official.
"It's impossible to warn authorities in advance because the borders between Latvia and the UK are open."
Anyone whose name features on the 'WI' database who attempts to cross the UK border is supposed to be "flagged" by the system, allowing immigration officers the opportunity to interview them, potentially leading to the traveller being arrested or refused entry to the country.
Disclosing the new information about Zalkalns, Mr Mehta said: "The conviction was in 1998 and he served a custodial sentence of seven years.
"I want the public's help. On Thursday August 28 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.
"Arnis has not been seen since Wednesday September 3. I want anyone who may have seen him after that date, or who may have helped him by giving him money or somewhere to stay, to call and speak to us. It is really important that we trace Arnis and speak to him about Alice's 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.
"Alice used social networking sites, Facebook, Twitter and Ask.fm. I'm asking anyone who may have been talking to Alice on these sites in the run up to the day she disappeared to speak to us."
Detectives in Latvia have confirmed that they are assisting Scotland Yard with the man-hunt for Zalkalns.
Toms Sadovskis, a spokesman for the Latvian police, said: "Latvian Police are cooperating with Scotland Yard. The Metropolitan police have asked us for information on Arnis Zalkalns and we are cooperating.
"We don't have information that Arnis Zalkalns is in Latvia.
"We sent the Met Police all the information about Arnis Zalkalns right after we got all the requests. I can't say it took us a long time to send the information over."
However, Latvian police declined to give further information about the 41-year-old's previous conviction.
Zalkalns is described by detectives as white, 5ft 10ins, of stocky build with dark brown hair. He normally wears his hair tied in a ponytail and often cycles to work on a red Trek mountain bike or a racing bike.
Detectives are offering a reward £20,000 for information that leads to Alice being found.
Alice Gross is described as white, 5ft 2ins and of very slim build with shoulder-length, light brown hair. On the day she disappeared she was wearing dark blue jeans and a grey top, and tartan framed glasses. She was carrying a dark rucksack, and wearing denim blue 'Vans' shoes. Her shoes were discovered in her rucksack when it was found by police on September 2.
In June last year Scotland Yard said the number of foreign criminals in Britain was far higher than previously thought, with new checks uncovering serious offenders who were previously unknown to the authorities.
For example, officers found more than 40 predatory rapists were living in London. Unlike home-grown offenders they were not subject to any controls such as reporting regimes or the sex offenders register.
Commander Steve Rodhouse disclosed police were using increasing amounts of information from foreign countries to secure deportation of offenders in Britain.
The Latvian embassy in London issued a statement on the police search for Zalkalns.
A spokesman said: "The embassy of the Republic of Latvia is aware that Mr Arnis Zalkalns is wanted by British authorities with regard to disappearance of Alice Gross."
"The embassy has not been contacted by British authorities on this matter and Mr Zalkalns has not contacted the Embassy.
"Nor does the embassy possess information about his whereabouts.
"We are following the case in close cooperation with Latvian National Bureau of Interpol which is cooperating directly with the Metropolitan Police on the case and has provided British authorities with all the necessary information.
"Should it be required,the embassy is ready to facilitate contacts and exchange of information between the relevant authorities.
"The embassy is not permitted to comment or disclose information related to the investigation."