More than 50 former intelligence officials, led by Obama-era Director of National Intelligence James Clapper, are trying to link the recent disclosure of emails purportedly belonging to Joe Biden’s son to a “Russian information operation.”

According to Politico, the former intelligence officials—some of them have endorsed Biden—have no evidence of Russia involvement but their national security experience had made them “deeply suspicious that the Russian government played a significant role in this case.”

“We want to emphasize that we do not know if the emails, provided to the New York Post by President Trump’s personal attorney Rudy Giuliani, are genuine or not and that we do not have evidence of Russian involvement,” they wrote in an open letter

“If we are right,” they added, “this is Russia trying to influence how Americans vote in this election, and we believe strongly that Americans need to be aware of this.”

The letter came after House Intelligence Committee Chairman Adam Schiff (D-Calif.), who has drawn criticism over making dramatic claims about President Trump’s alleged ties to Russia, claimed last week that the emails are part of a smear coming “from the Kremlin.”

“We know that this whole smear on Joe Biden comes from the Kremlin,” Schiff said on CNN. “That’s been clear for well over a year now that they’ve been pushing this false narrative about this vice president and his son.”

Documents declassified by Director of National Intelligence John Ratcliffe earlier this month revealed that former CIA Director John Brennan briefed former President Barack Obama on Hillary Clinton’s purported “plan” to tie then-candidate Donald Trump to Russia as “a means of distracting the public from her use of a private email server” ahead of the 2016 presidential election.

Ratcliffe asserted Monday that the emails were not part of a Russian disinformation campaign.

“Let me be clear: The intelligence community doesn’t believe that because there is no intelligence that supports that. We have shared no intelligence with chairman Adam Schiff or any other member of Congress that Hunter Biden’s laptop is part of some Russian disinformation campaign,” he said in an interview on Fox News.

While Democrats have suggested that the emails are part of a Russian information operation, the Biden campaign and Hunter Biden have not disputed the veracity of the emails.

Hunter Biden’s lawyer even contacted the computer repair shop owner who found the compromising material contained in the laptop, and asked that he return the hard drive, according to Rudy Giuliani, who obtained a copy of the hard drive.