Russian officials have criticised a lack of communication by US authorities over the death of Mikhail Lesin, a former aide to President Putin.
They said they became aware of details of his injuries only when the medical examiner's report was released on Thursday.
Mr Lesin, 57, was found dead in a US hotel four months ago. US coroners say he died of head injuries.
Medical examiners say the exact circumstances of death are not clear.
Russian media had reported his death as a suspected heart attack.
He was one of the most influential figures on the Russian media scene.
The Russian embassy in Washington told the BBC that it became aware of the injuries sustained by Lesin only on Thursday, when the medical examiner's report was released.
Press Secretary Yuri Melnik said Russia had made repeated requests for updates on the investigation but very few facts had been given.
Kremlin spokesman Dmitry Peskov said no detailed information about the case had been provided to Moscow via the channels used for such cases.
"In the light of these media reports we hope that we will receive the detailed information," he said.
Washington DC's chief medical examiner said Mr Lesin had, as well as head injuries, blunt force injuries to the neck, torso, arms and legs, without concluding how the injuries had been sustained.
Police spokesman Dustin Sternbeck said the case remained under investigation, the Washington Post reports.
He declined to say whether the post-mortem examination results meant a crime might have been committed.
The New York Times reported that Mr Lesin's injuries were the result of "some sort of altercation" that happened before he returned to his hotel.
A former Russian press minister and one-time head of the powerful Gazprom-Media Holding group, Mikhail Lesin was found dead on 5 November 2015 in the Dupont Circle Hotel.
It is unclear why he was in Washington but several family members were resident in the US and had business interests there.
He worked as an aide to the presidency between 2004 and 2009 and was instrumental in the creation of Russia's state-funded international broadcaster RT (formerly known as Russia Today).
The BBC's Steve Rosenberg in Moscow says that for years Mr Lesin was the mastermind behind the Kremlin's wholesale takeover of the Russian media landscape after Vladimir Putin became president.
As Russian press minister and media adviser to the president, he earned the nickname The Bulldozer for the way in which he crushed all Kremlin critics in his path, our correspondent says.
After Mr Lesin's death, President Putin spoke of his "enormous contribution" to Russian media.
Various theories are swirling in the media about what happened to Mr Lesin now it has it emerged that he suffered multiple injuries.
Last November the UK's Daily Mail raised the possibility that the FBI could have faked Lesin's death in order to give him witness protection - as a valuable information source, since he had long been a Kremlin insider.
It also quoted Mikhail Seslavinsky, head of Russian media regulator Rospechat, as saying Mr Lesin had appeared happy and healthy a month earlier. He added that he had undergone complicated surgery for a spinal injury, but was now practising sports.
There are unconfirmed reports that Mr Lesin had had a dispute with financier Yuri Kovalchuk, a longstanding friend of Mr Putin.
A Russian forensic expert quoted by Lenta.ru website (in Russian), Alexander Aulov, said Mr Lesin's injuries were consistent with a severe beating, not an accident or the result of convulsions.
In 2014, Mississippi Senator Roger Wicker called for an investigation into Mr Lesin over possible money laundering, saying he had moved his family to the US and bought several multi-million dollar properties in California.
Some of the properties reported to have been bought by companies connected to the family include, according to the LA Times, a house in the Pacific Palisades for almost $4m and a house in Beverley Hills bought in 2011 for almost $14m.
His son Anton Lessine has produced several high-profile Hollywood films, the Business Insider website reports, featuring stars like Brad Pitt, Woody Allen and Arnold Schwarzenegger.
Lesin's Gazprom-Media group is owned by Gazprombank which, in turn, has links to Bank Rossiya, described by the the EU and US authorities as "the personal bank" of top Russian officials.
Bank Rossiya is under EU-US sanctions, as is the bank's biggest shareholder Yuri Kovalchuk. He is a longstanding close aide to President Putin.