Five Republican senators are calling on U.S. Attorney General Loretta Lynch to drop any investigations into private entities’ views on climate change, a probe that the Department of Justice has not acknowledged is ongoing.

A letter to Lynch was sent Wednesday by Sens. Jeff Sessions of Alabama, David Perdue of Georgia, David Vitter of Louisiana, Ted Cruz of Texas and Mike Lee of Utah. The letter regards comments that Lynch made during an oversight hearing in March of the Justice Department before the Senate Judiciary Committee.

At the hearing, Sen. Sheldon Whitehouse (D-RI) questioned Lynch and said under President Clinton, Justice had “brought and won” a civil RICO (Racketeer Influenced and Corrupt Organizations) Act action “against the tobacco industry for its fraud. Under President Obama, the Department of Justice has done nothing so far about the climate denial scheme.”

Lynch responded that Justice had “received information about it and have referred it to the FBI to consider whether or not it meets the criteria for what we could take action on.”

Information into whether an official inquiry is being done has not been released. However, the senators pointed to Justice being asked in 2015 by a coalition of “environmentalists and lawmakers” to investigate whether “the past decisions of a private sector company to adopt and publicly disclose certain views on climate issues, and to refrain from adopting and publicly disclosing others, may have violated the RICO Act and related laws.”

ExxonMobil was not named specifically in the letter, but it is the only high profile company now being questioned about its internal climate change research. Several states and stakeholder groups, led by New York AG Eric Schneiderman, last fall began probing ExxonMobil’s 30-plus years of research about the impact of oil and gas operations and whether it concealed information (see Daily GPI, April 15; Nov. 6, 2015; Oct. 23 2015). ExxonMobil since 2007 has published information about the business risks of climate change in its annual U.S. Securities and Exchange Commission 10-K filings, corporate citizenship reports and other documents provided to shareholders. About a decade ago ExxonMobil also began using a proxy cost for carbon in its internal planning.

The state investigations are part of a big government scheme, the senators said.

“These actions provide disturbing confirmation that government officials at all levels are threatening to wield the sword of law enforcement to silence debate on climate change,” they said. “As you well know, initiating criminal prosecution for a private entity’s opinions on climate change is a blatant violation of the First Amendment and an abuse of power that rises to the level of prosecutorial misconduct…”

The senators asked for reassurance by Lynch within two weeks that “all investigations and inquiries” had been terminated.