FBI Director James Comey played a role in 2017's biggest sell-off, says Jim Cramer

FBI Director James Comey testifies before the House Intelligence Committee hearing into alleged Russian meddling in the 2016 U.S. election, on Capitol Hill in Washington, U.S., March 20, 2017.
Joshua Roberts | Reuters

FBI Director James Comey played a role in the stock markets worst day of the year, CNBC's Jim Cramer said Wednesday.

"I think Comey scared a lot more people than people want to talk about," Cramer said on "Squawk on the Street," referring to when Comey testified before the House Intelligence Committee on Monday.

The FBI director confirmed the agency is investigating Russia's influence on the 2016 U.S. election, despite President Donald Trump calling reports on Russian ties "fake news."

"Comey comes out ... and uses the word criminal in the same context and that makes people feel like we can rebel against this guy," Cramer said.

On Tuesday, U.S. equities posted their worst day of the year as investors turned their eyes to a key House vote on an Obamacare replacement and markets doubted Trump's pro-growth policies.

The House is expected to vote Thursday on repealing and replacing the Affordable Care Act, better known as Obamacare. Market strategists say the success or failure of the vote could be an indicator for future Trump legislation like tax reform.

On Tuesday, Trump warned wavering House Republicans that their jobs were on the line if they failed to back the bill.