Donald Trump adviser John Eastman’s emails may have evidence the former president and his associates committed crimes in attempting to prevent Congress from certifying the 2020 election results, a House committee investigating the Jan. 6 insurrection said in a court filing.

It’s the first public signal that the committee is looking into criminal activity by those within Trump’s inner circle.

The committee says the emails may contain evidence of obstruction of an official proceeding — a felony that carries a maximum sentence of 20 years in prison — a conspiracy to defraud the U.S. and common law fraud.