The investigation by three attorneys general into what Exxon Mobil knew about climate change and when is driven by political desire to push climate change policies, West Virginia's attorney general said Tuesday.

Speaking on the "Inside Shale Weekly" radio show in West Virginia, Patrick Morrisey said he was deeply disappointed by the attorneys general from New York, Massachusetts and the U.S. Virgin Islands investigating Exon Mobil for possibly covering up its knowledge of climate change.

Morrisey said he believed the attorneys general are abusing the powers of their office and said he was "disappointed."

"They're looking at additional measures in order to address their policy ideas, but that's not what it's about to be attorney general," he said. "You cannot use the power of the office of attorney general to silence your critics."

New York Attorney General Eric Schneiderman announced he is investigating what Exxon Mobil knew and when, and reports indicate California Attorney General Kamala Harris began doing the same in January. Last week, Massachusetts Attorney General Maura Healey and U.S. Virgin Islands Attorney General Claude Earle Walker announced they would do the same.

The investigations stem from media reports that Exxon Mobil learned in 1977 from a senior scientist that burning fossil fuels would warm the planet. A year later, the company began researching how carbon dioxide released from the burning of fossil fuels would affect the planet.

Six years after the internal document was produced, Exxon Mobil went on the offensive, according to the report. The company began paying for efforts that would cast doubt on climate change, including founding the Global Climate Coalition.

At the same time, the company was building climate change projections into the company's future plans. Among those plans was future drilling in the Arctic because the polar ice caps would melt.

Exxon Mobil has repeatedly denied the claims and has cast aspersions on the media reports, noting that Inside Climate News received funding from the Rockefeller Brothers Fund, which works against climate change.

Morrisey, who is one of the 30 attorneys general suing the Obama administration to block the Clean Power Plan regulations on power plants, said he believed the attorneys general are acting because they're concerned the regulation may be struck down.

The Supreme Court stayed the plan in February until legal challenges are completed. Morrisey said he thinks the attorneys general got "more aggressive" after that.

"They want to eliminate fossil fuels and that should not be driving anything," Morrisey said. "I won't speak to whether it does, but it should not be driving any legal activity."