"Detectives are asking for the public's help in their continued investigation to find the missing teenager Alice Gross. Alice went missing two weeks ago today, on Thursday 28 August, and has not been seen since," police said in an appeal for help.
"Detectives have pieced together the last known sightings of Alice on that Thursday from CCTV, but they still have not heard from any witnesses who actually saw her after 1630 that day."
Arnis Zalkalns, who has served a sentence for murder in Latvia, was named by police as a suspect after CCTV footage showed him cycling in the same direction in which the teenager was seen.
Zalkalns was also previously arrested in connection with an alleged indecent assault on a teenage girl in West London, though no charges were brought.
"Arnis Zalkalns was seen on CCTV cycling along Brentford Lock at 1600hrs, some 15 minutes after Alice walked that route at 1545hrs.
"Detectives believe he is likely to have come across Alice as they were both going in the same direction, north along the canal towpath. What, if anything, happened there is now one of the focuses of this investigation," the police statement said.
Since 41-year-old Zalkalns was last seen at his home in Ealing on the evening of Wednesday, 3 September he has not accessed his bank account or used his mobile phone. His passport was left at his house.
Detective Superintendent Carl Mehta, from the Homicide and Major Crime Command, said:
“I want the public’s help. On Thursday 28 August Arnis Zalkalns left work, in Isleworth, at about 3.30pm on his bike.. I 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 3 September. 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."
Arnis Zalkalns is white, 5ft 10ins of stocky build with dark brown hair that he normally wears wears in a pony tail.
A reward of up to £20,000 is being offered for anyone who has information that leads detectives to find Alice Gross.
Anyone with information about Zalkalns' whereabouts is urged to contact the investigating officers direct on +44 (0)20 8358 0100 or to pass information via local Latvian police.