One of Russia’s top legal officials who frequently spearheaded Vladimir Putin’s criticisms of Britain has been killed in a mystery helicopter crash.

A shocking video showing burning debris of the stricken AS-350 in Kostroma region northeast of Moscow has been released by Russian law enforcement officials.

Among the three confirmed dead was 58 year old deputy Russian prosecutor general Saak Karapetyan, a vitriolic critic of Britain over the Sergei Skripal case and other disputes.

He was in overall charge of Russian criminal cases into the Skripal poisoning, as well as the deaths of Vladimir Putin foe Boris Berezovsky, and the London poisoning with polonium-201 of dissident Alexander Litvinenko.

Saak Karapetyan, 58, Russia's deputy prosecutor general and one of Putin's top legal advisors has died in a helicopter crash (
Image:
IC Russia/east2west news)

His death on impact was confirmed more than 12 hours after the crash yesterday evening with some reporting four were killed in the crash.

The initial theory is that the French-made AS-350 helicopter was being used for a hunting trip.

Hunting rifles were reportedly found amid the wreckage at the crash site 365 miles north east of Moscow.

The helicopter clipped trees while flying at night and this was the “reason for the crash”, according to another report.

But it was also claimed the helicopter was flying to Plyos, a town on the Volga River where premier Dmitry Medvedev is believed to have a holiday home.

It's been reported that four people were killed in the crash (
Image:
IC Russia/east2west news)

"The wreckage of the helicopter was found near the village of Vonyshevo, the aircraft was burned,” added an emergencies ministry source cited by Tass.

"The debris of the crashed helicopter have been found. Three people died in that crash.

"Their bodies were also found at the crash site," the source said.

The Investigative Committee has launched a criminal probe into the helicopter crash, it was announced.

Also killed was a man named Arek Aratunyan.

The pilot Stanislav Mikhnov, 54, who also died in the crash was described as highly experienced.

In April, Karapetyan had blasted Theresa May’s government over the Skripal poisoning.

He said: ”The British authorities have based the anti-Russian campaign surrounding the poisoning of former GRU officer Skripal and his daughter on a provocative scenario.

“A similar scenario was used in baseless allegations of Russia's attempt on the life of Boris Berezovsky in London in summer 2003 and the circumstances surrounding the death of Alexander Litvinenko in the UK in November 2006.

"I should say that the targets of those three provocations were persons charged with grave felonies in Russia who repeatedly made statements criticising the Russian authorities.

There are reports the passengers were going on a hunting trip (
Image:
IC Russia/east2west news)

“A false motive for their physical liquidation was thus created.”

In each of those three cases, there was 'a massive leak' of baseless allegations that Russian security services used toxins on the British territory, he complained.

”Demands that sanctions be imposed on Russia were made in that connection," he said.

"In those three cases the British authorities acted in disagreement with the European Convention on Mutual Assistance in Criminal Matters of 1959, refused to interact with Russian law enforcement agencies, and classified the progress and results of inquiries, which made any third-party assessment of their impartiality impossible.”

He led Russian criminal investigations into all three cases.

(
Image:
IC Russia/east2west news)

He said in April: "As long as the matter concerns our citizens, in this particular case these three people [Skripal, Berezovsky and Litvinenko], we have opened criminal investigations and are conducting them ourselves. The investigations into these cases have not stopped.”

Demanding British cooperation he said: "We will continue to conduct these investigations with the purpose of a complete and more impartial examination of all circumstances of the crimes committed against our citizens.”

He stressed relations with the UK were “not so good”.

Despite his criticisms of Britain, his daughter Diana, 32, is believed to live in London.

His widow Karine is a wealthy property owner.

The crash happened in the Kostroma region northeast of Moscow (
Image:
IC Russia/east2west news)

He said: ”53 out of 60 denials were explained with political motives behind the prosecution and the allegation that the extradition would breach human rights."

Karapetyan was born in 1960 in Rostov region.

He got his degree in law in Rostov State University.

He was a prosecutor who became an MP and was deputy chairman of the Duma's committee for security.

Since 2000 he worked on various positions in general prosecutor office and ministry of justice.

In 2016 was appointed deputy general prosecutor.