THE BURNED OVER DISTRICT

And the investigation into Exxon Mobil's decades long efforts to distort and cover up climate change research has been growing lately.

Attorneys general from Massachusetts and the Virgin Islands announced Tuesday that they would join Eric T. Schneiderman, New York’s attorney general, in his investigation into whether Exxon Mobil lied in decades past to investors and the public about the threat of climate change.

The additional participation was announced during a news conference at Mr. Schneiderman’s offices in Lower Manhattan announcing support from 15 states, the District of Columbia and the Virgin Islands for the Obama administration’s Clean Power Plan.

Attorneys general from Vermont, Maryland, Massachusetts, Virginia, Connecticut and the Virgin Islands, as well as former Vice President Al Gore, attended the event.

While none of the other officials present, aside from Maura Healey of Massachusetts and Claude Walker of the Virgin Islands, announced inquiries of their own, Mr. Schneiderman said, “not every investigation gets announced at the outset.”

Mr. Schneiderman began his investigation in November. His staff is looking at whether statements the company made to investors about climate risks — some as recently as last year — conflicted with the company’s own scientific research.

Part of that inquiry includes the company’s funding, for at least a decade, of outside groups that worked to dispute climate science, even as its in-house scientists were describing the possible consequences of climate change, along with the areas of uncertainty.

Mr. Schneiderman said, “The First Amendment, ladies and gentlemen, does not give you the right to commit fraud.”

The attorneys general have a range of laws to work with, including the Racketeer Influenced and Corrupt Organizations Act, or RICO. Mr. Schneiderman has statutes specific to New York, including the Martin Act, which gives the government broad investigative powers; laws allowing the state to take action against “persistent fraud or illegality”; and the state’s deceptive business and trade practices act.

Or as Sir Walter Scott wrote, “Oh, what a tangled web we weave...when first we practice to deceive".