FORTUNE — Last night, just eight days before its civil racketeering suit against environmental lawyer Steven Donziger is scheduled to commence in Manhattan, Chevron asked U.S. District Judge Lewis Kaplan to review privately a batch of mysterious documents that turned up last month which the oil giant says may be relevant to “claims that certain parties were conspiring against Chevron in connection with the Lago Agrio litigation.”

Chevron’s new submission alleges that the emails, some of which were to and from a high-level legal advisor to Ecuadorian president Rafael Correa, show that a confidential document filed in Chevron’s racketeering case was leaked in violation of Kaplan’s protective orders.

For those coming in late, the skeletal backdrop is this: In 2003, the Amazon Defense Front, assisted by U.S. attorney and strategist Donziger, brought an environmental suit against Chevron in Lago Agrio, Ecuador, alleging wrongdoing by Texaco (acquired by Chevron in 2011) when it drilled there from 1964 to 1992. In February 2011 that suit culminated in a $19 billion judgment against Chevron. That same month Chevron filed a federal suit against Donziger and the Front in Manhattan under the Racketeer Influenced and Corrupt Organizations Act (RICO), alleging that the $19 billion judgment was procured through bribery, extortion, mail fraud, wire fraud, obstruction of justice, witness tampering, and money laundering. The government of Ecuador—which settled all its environmental issues with Texaco in 1998—is not a party to the Lago Agrio case, but President Correa has aggressively championed the Front’s suit, even to the point of recently branding Chevron’s Ecuadorian witnesses and attorneys as “traitors,” “criminals,” and “collaborators.”

Chevron was alerted to the existence of the mystery documents on September 24, its filing says, when an assistant to lead lawyer Randy Mastro received an unsolicited call from Margaret Petito, who is “an individual unaffiliated with Chevron.” (She is, according to a brief interview with Fortune, the president of a “very small” Washington, D.C.-based non-profit called Friends of Rule of Law in Ecuador, Inc., which was incorporated in 2001.) Petito left a message with Mastro’s assistant stating that she had been emailed certain documents anonymously that she believed might be “relevant to the case,” according to an affidavit from Petito that was included in last night’s submissions. (Petito also states there that she has received no compensation from Chevron and forwarded the materials because she “thought it was the right thing to do.”)

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Chevron then retained an Austin, Texas lawyer that it has used in the past, but who has not previously been involved in the Lago Agrio or RICO matters, to contact Petito and take possession of her documents on September 27. That lawyer, Patton Lochridge of McGinnis Lochridge, then supplied a declaration stating that many of the emails included Alexis Mera, a legal advisor to Correa, as either an email sender or recipient, and that one of these included as an attachment a confidential document that Chevron had filed in the RICO case under a protective order which should have barred it from being shown to someone like Mera. Lochridge said that at least some of the emails might be subject to attorney-client privilege, but he couldn’t tell due to general lack of familiarity with Chevron’s RICO case and his lack of knowledge as to how the emails came to light.

Chevron is asking that the documents be reviewed privately (or “in camera”) by Judge Kaplan or one of the two special masters he has appointed to assist on discovery matters. Chevron also asks, of course, that the documents, if found to be relevant and unprivileged, be turned over to its lawyers on the RICO case.

An email and call to Eric Bloom—a Winston & Strawn attorney who has represented the Republic of Ecuador in connection with an international bilateral investment treaty (BIT) arbitration Chevron has brought against the Ecuador over the Lago Agrio litigation—were not immediately returned. A spokesman for Donziger said the papers were a “surprise,” and he would have more to say later today. A spokesperson for the Amazon Defense Front said he was awaiting a response from his clients.