(Saul Loeb/AFP/Getty Images)

This post has been updated.

Lawyers for ExxonMobil have told a variety of non-governmental organizations to preserve all communications regarding climate change investigations with a sweeping array of other groups and individuals — including members of the press.

The letters from Exxon’s lawyers Paul Weiss Rifkind Wharton & Garrison said the groups, including the Union of Concerned Scientists and the Rockefeller Family Fund, should hang onto communications with individuals such as former vice president Al Gore and William McKibben, a Middlebury professor and leader of the environmental group 350.org.

The letters are the latest twist of a legal saga in which Massachusetts attorney general Maura Healey and New York attorney general Eric Schneiderman have publicly announced inquiries into whether ExxonMobil improperly concealed information about climate change from consumers, investors and the public long after it knew the dangers. As part of those probes, the attorneys general have issued subpoenas for documents going back as far as the 1970s.

If ExxonMobil were found to have concealed such information that could be a violation of the Martin Act, which gives the New York attorney general broad power to pursue fraud cases. Schneiderman and other attorneys general, in an unusual step, held a press conference that included Gore in March vowing to work together to combat climate change, including through the investigation of ExxonMobil.

The company has alleged Healey and Schneiderman were biased and it has fought back in a Texas federal district court, where Judge Ed Kinkeade said there was reason enough to allow Exxon to seek documents from Healey that might show she prejudged the matter.

However, a New York Supreme Court judge recently ordered Exxon and its accounting firm to comply with Schneiderman’s subpoena.

Exxon appears to be relying on the Texas ruling to issue the latest letters to non-governmental organizations.

“Our request to preserve documents is focused on groups or individuals directly involved in a campaign to discredit our company using false allegations and mischaracterizations of the company’s history of climate research and communications with investors,” Alan T. Jeffers, an ExxonMobil spokesman, said in an email. “We have no choice but to defend ourselves against politically motivated investigations that are biased, in bad faith and without legal merit.”

“We did not start this, but we will see it through and will vigorously defend ourselves.”

Lee Wasserman, director of the Rockefeller Family Fund, set up in large part with money from the Standard Oil fortune, said Exxon sought “to protect a destructive, obsolete business model ushering in the climate catastrophe its scientists long ago predicted, rather than evolving into a corporation for the 21st century.”

“How tragic that the management of a once great corporation would permit itself to devolve into a civic bully committed to intimidation of public interest advocates,” Wasserman said.

“We’re not a party to this litigation,” said Kenneth Kimmell, president of the Union of Concerned Scientists. “It raises questions about how an [non-governmental organization] like UCS can be dragged into a legal fight between Exxon and the attorney general.”

He added that it would “very burdensome” for the group to comply if a court or prosecutor were to issue an actual subpoena to produce such documents.

“The letter that we received from ExxonMobil’s lawyers signals that  the company is planning a massive fishing expedition into UCS’s internal e-mails and communications with others, including the press,” Kimmell said in an email. “We don’t see how this relates to the company’s current disputes with the New York and Massachusetts Attorneys General, and it appears to be yet another effort to intimidate us from exposing climate science deception.”