Congress has been investigating possible Trump campaign collusion with the Kremlin for nearly 10 months, but a top Senate Democrat says she has still not seen evidence to support the allegation.

“Have you seen any evidence that this dirt, these emails, were ever given to the Trump campaign?” CNN’s Jake Tapper asked California Sen. Dianne Feinstein on Sunday.

“Not so far,” replied the Democrat, who is a member of the Senate Intelligence Committee and the ranking Democrat on the Senate Judiciary Committee.

Both panels are investigating various aspects of Russian interference in the presidential campaign.

Tapper was asking Feinstein about revelations this week that former Trump campaign adviser George Papadopoulos told the FBI that he was in talks with a London-based professor with Kremlin connections who claimed in April 2016 to have learned that the Russian government had “dirt” on Hillary Clinton in the form of “thousands” of her emails.

It is still unclear whether Papadopoulos, who pleaded guilty last month to lying to the FBI, told members of the Trump campaign about the emails. The professor, Joseph Mifsud, has accused Papdopoulos of lying.

The idea that the Trump campaign coordinated with Russian operatives to hack into and disseminate Democrats’ emails has been a core theory of the collusion allegation. That theory rests largely on a dossier funded by the Clinton campaign and Democratic National Committee.

The dossier alleges a “well-developed conspiracy of cooperation” between the Trump campaign and Russian leadership. It also alleges that Russians hacked Democrats’ emails and gave them to WikiLeaks “with the full knowledge and support of Trump and senior members of his campaign team.”

Feinstein says she has not seen evidence to back up the allegation.

“Have you seen any communications that suggested that the Trump campaign wanted them to release [emails] through a different means? Because obviously they were ultimately released by Wikileaks,” said Tapper.

“No, I have not,” Feinstein responded.

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