24 December 2014 Last updated at 14:35
MH17: Russia reveals 'witness' who blames Ukraine pilot
Flight MH17 from Amsterdam to Kuala Lumpur was shot down over rebel-held territory in eastern Ukraine
Russian investigators say a Ukrainian serviceman has provided evidence that a Malaysia Airlines plane that crashed in July may have been shot down by a Ukrainian air force pilot.
A "secret witness" told a Russian newspaper this week that an Su-25 fighter pilot had fired his air-to-air missiles at the wrong aircraft.
Ukraine has rejected the claim as fake.
Flight MH17 from Amsterdam was downed over eastern Ukraine on 17 July with the loss of all 298 people on board.
Suspicion immediately focused on a Russian-made Buk missile launcher seen in territory controlled by pro-Russian rebels at the time.
The head of the Dutch-led criminal inquiry, Fred Westerbeke, told Dutch broadcaster NOS on Saturday there were "very many indications" that the plane had been brought down by a missile filed from a Buk rocket launcher.
However, all options were being kept open and the possibility of the plane being shot down from the air was being considered, he said.
Russia's authorities have already suggested that a Ukrainian fighter jet brought the plane down, however when state TV broadcast a picture of the moment it said an air-to-air missile had been fired, it was widely dismissed as a fake.
The latest Russian evidence came to light after a man contacted Komsomolskaya Pravda newspaper, saying he had been at Aviatorske airport near the Ukrainian city of Dnipropetrovsk when flight MH17 was shot down.
In an interview in Russian with his back to the camera, the man, whose head was blurred and his voice digitally altered, said that an Su-25 plane that had taken off armed with air-to-air missiles before MH17 had been shot down had returned without its weaponry.
He named the pilot as Capt Voloshyn and said the man was very scared. He quoted the pilot as saying "the aircraft was in the wrong place at the wrong time".
His comments were widely reported on Tuesday on Russian state TV and Russia's Investigations Committee announced immediately that it would look into the interview.
A committee spokesman, Vladimir Markin, told reporters on Wednesday that investigators had met the man and he had passed a polygraph test.
"The witness's evidence is not the only [evidence] but [it is] very important evidence that the Ukrainian armed forces were involved in the Boeing crash," Interfax news agency quoted Mr Markin as saying. The man could now be given witness protection as he may be in danger, he added.
Ukraine's SBU security service refused to comment on the statement because it said the information was false, Interfax Ukraine reported.
The Dutch Safety Board, leading an international inquiry into the cause of the disaster, has so far only issued a preliminary report stating that the aircraft was penetrated by "high-energy objects".
A spokeswoman told BBC News that the inquiry had received a lot of information and Russia was part of the investigation team. "We'll look at [the evidence] very seriously and if it's relevant we'll use it in this investigation."
Wreckage from the crashed Boeing 777 plane has been transported to the Netherlands for reconstruction as part of the inquiry.
The safety board aims to complete its work by mid-2015.