A bombshell piece of evidence in a lawsuit between Uber and Alphabet’s Waymo is now public.

Previously discussed only in court testimony, a letter in May from the attorney of former Uber security analyst Richard Jacobs to Uber’s internal counsel contains an exhaustive list of illegal activities that Jacobs said he witnessed while employed at the company from March 2016 through April 2017.

Jacobs, who previously worked for the Defense Intelligence Agency, claims to have seen fraudulent activity and theft of information at Uber’s strategic services group and is aware of Uber’s marketplace analytics team “fraudulently impersonating riders and drivers on competitive platforms.” The letter alleges he witnessed illegal wiretapping and an extensive effort to “unlawfully obtain trade secrets.”

The 37-page letter, unsealed late on Friday, also alleges that Uber’s security team told staffers to use ephemeral messaging systems like Wickr and non-attributable devices to hide their actions to protect the company from potential litigation.

Jacobs’s lawyer sent the letter to Angela Padilla, Uber’s deputy general counsel, after Jacobs left the company. Padilla said in court testimony that the letter was an attempt by Jacobs to extort money from Uber.

Addressing the allegations made in the letter, an Uber spokesperson said, “While we haven’t substantiated all the claims in this letter — and, importantly, any related to Waymo — our new leadership has made clear that going forward we will compete honestly and fairly, on the strength of our ideas and technology.”

Alphabet’s Waymo sued Uber in February, claiming that former Waymo engineer Anthony Levandowski downloaded more than 14,000 confidential files from Waymo before leaving to set up self-driving truck company Otto, which Uber acquired soon after.

In court testimony, Jacobs publicly denied parts of the letter, saying he didn’t stand by the statement that Uber surveilled its competitors and stole trade secrets from Waymo.

Judge William Alsup delayed the trial on Nov. 28, after a U.S. attorney sent him the Jacobs letter, saying Uber should have turned over this evidence. A special master presiding over the trial issued a ruling earlier on Friday that Uber should have submitted the Jacobs letter during the discovery process.

Padilla testified that some Uber board members knew about the letter. They include Bill Gurley, Garrett Camp, Ryan Graves, David Bonderman, Wan Ling Martello, Arianna Huffington, and Travis Kalanick.

Uber settled with Jacobs for $4.5 million when he resigned.

The trial between Uber and Waymo is set to start Feb. 5.