The oil giant asked the Massachusetts Superior Court on Thursday to bar state Attorney General Maura Healey from continuing an investigation into what she and a coalition of attorneys general say is a company cover-up of its scientists’ research showing the risks posed by climate change.

The company adamantly denies that it has suppressed information. The campaign against the company is based on news reports that in the 1970s, Exxon scientists found that burning fossil fuels would cause substantial harm to the Earth’s climate, but the company did not share the findings.

Thursday’s lawsuit follows a motion filed by the company Wednesday in a Texas federal court requesting that the court block Healey’s investigation with an injunction.

Her investigation “violates Exxon Mobil’s constitutional, statutory, and common law rights, as well as the standards of Massachusetts, which protect Exxon Mobil from ‘annoyance, embarrassment, oppression, or undue burden or expense,” according to the Exxon’s motion filed in the state.

The free-market think tank Competitive Enterprise Institute, which also has been targeted by the Democratic attorneys general, welcomed Exxon’s court actions.

The think tank has a case pending against Claude Walker, the attorney general for the U.S. Virgin Islands, in D.C. Superior Court. CEI is asking the court to sanction Walker.

Soon after he filed the territory’s motion last month, Walker withdrew his subpoena asking the think tank for a decade of emails and correspondence with members and supporters.

“We all understand the need for a healthy environment, but we represent a wide range of viewpoints regarding the extent to which man contributes to climate change and the costs and benefits of any proposed fix,” it said. “Nevertheless, we agree on at least one thing — this is not a question for the courts. Using law enforcement authority to resolve a public policy debate undermines the trust invested in our offices and threatens free speech.”

The coalition is made up of 13 attorneys general from Alaska, Oklahoma, Nevada, South Carolina, Louisiana, Arkansas, Wisconsin, Arizona, Utah, Nebraska, Alabama, Michigan and Texas.