The FBI never asked the Democratic National Committee if it could examine a computer server that was the subject of cyber attacks last year.

Instead federal law enforcement relied on data that, Crowdstrike, a private computer security company, gathered from the device.

The FBI later endorsed the conclusion that Russian intelligence services were behind the hacking, and that their goal was to help Donald Trump win the November presidential election.

The Federal Bureau of Investigation never asked the Democratic National Committee to see the computer server that the U.S. government now claims was hacked by Russians

Senate Armed Services Committee Chairman John McCain (center) blasted 'Russia's attacks on our nation' during a hearing Thursday with top intelligence officials

'The DNC had several meetings with representatives of the FBI's Cyber Division and its Washington Field Office, the Department of Justice's National Security Division, and U.S. Attorney's Offices, and it responded to a variety of requests for cooperation,' DNC deputy communications director Eric Walker told BuzzFeed, 'but the FBI never requested access to the DNC's computer servers.'

Trump's incoming press secretary Sean Spicer told reporters on a Thursday morning conference call that 'the DNC is on the record saying the FBI never contacted them to validate claims by Crowdstrike, which is the third-party tech security firm, and never actually requested the hacked server.'

'You know, I would equate this to no one actually going to a crime scene to actually look at the evidence,' Spicer declared.

Walker said there were no restrictions on what the FBI could request from its private security company's findings.

'Beginning at the time the intrusion was discovered by the DNC, the DNC cooperated fully with the FBI and its investigation, providing access to all of the information uncovered by CrowdStrike - without any limits,' he said.

Donald Trump seemed on Wednesday to back WikiLeaks founder Julian Assange's insistence that Russia was not behind election-year hacks of Democrats' computers and e mails

But the FBI's decision to leave the forensic investigation in the hands of a for-profit company will shed new doubts on the Obama administration's only public conclusion so far, that hackers tied to Moscow were responsible.

'There's just no way to be sure the FBI was making decisions based on solid evidence,' a Republican Senate aide told DailyMail.com on Friday, requesting anonymity to speak freely.

'This would be like the National Weather Service predicting with 100 per cent certainty that there will be three feet of snow in New York tomorrow, based on weather radar that it doesn't control.'

A report last from the FBI and Homeland Security department described how those agencies believe Russians gained control of the DNC's server

An unnamed intelligence official who spoke to Buzzfeed said the FBI routinely relies on Crowdstrike and other companies like it to analyze computer hardware in order to inform its own investigators.

'Crowdstrike is pretty good. There's no reason to believe that anything that they have concluded is not accurate,' the intelligence official told BuzzFeed.

But critics pointed to a similar investigation in 2014, where a 'par for the course' FBI probe included seizing a hacked computer server.

When North Korean operatives hacked into Sony Corporation's computers that year, the FBI got directly involved with the data-gathering.

The Senate staffer said 'my boss' believes there are 'a lot of holes in the Obama administration's theories right now.'

'The best they can say is that these DNC hacks look like things Russians have done before, but now we're learning that you can get the same tools from the Ukraine. They probably can't put anyone's actual fingerprints on any of this.'

President-elect Trump is due to receive a detailed briefing about the hacking from America's top intelligence officials on Friday.

Spicer, his spokesman, this week questioned the value of a technical-assistance report issued last week by the FBI and the Department of Homeland Security. That document laid out a case for believing the Russian government orchestrated the hacking.