Christopher Wylie, who leaked information on the British-based firm's hijacking of data on millions of Facebook users, told a Senate panel he believes Russian intelligence services had access to data harvested by the consultancy.
Wylie told the panel that Russian-American researcher Aleksandr Kogan, who created an application to harvest Facebook user profile data, was working at the same time on Russian-funded projects, including "behavioral research", Presstv Reported.
"This means that in addition to Facebook data being accessed in Russia, there are reasonable grounds to suspect that CA may have been an intelligence target of Russian security services...(and) that Russian security services may have been notified of the existence of CA's Facebook data," Wylie said in his written testimony.
Wylie added that Cambridge Analytica "used Russian researchers to gather its data, (and) openly shared information on 'rumor campaigns' and 'attitudinal inoculation'" with companies and executives linked to the Russian intelligence agency FSB.
The hearing is part of a broad inquiry on both sides of the Atlantic over the misuse of Facebook data by the consulting firm working on Donald Trump's 2016 campaign.
Facebook has accused Cambridge Analytica of misappropriating its user data by violating terms of the data agreement with Kogan, the academic researcher.
Wylie told the panel that "the ethos of the firm was 'anything goes'" for its political campaigns, including "attempting to divert health ministry funds in a struggling African country to support a politician's re-election campaign."
He added that he was aware of "black ops" at the company, "which I understood to include using hackers to break into computer systems to acquire kompromat or other intelligence for its clients."