Anthony Levandowski, the ex-Google engineer at the center of with ride-hailing company Uber, “personally owned and controlled” a competing self-driving car startup while he was still employed by Google, the company said in court filings Thursday. Soon after he left Google for Uber, the ride-hailing company purchased the startup.

Waymo, Google’s self-driving car project, has accused Uber of hatching a plan with Levandowski to steal Google’s self-driving car secrets and use them to advance the ride-hailing company’s own autonomous vehicle ambitions. After leaving the company, Levandowski launched a self-driving truck start-up called Otto, which was acquired within months by Uber for $680 million. Otto, Waymo claims, to seamlessly bring the documents to his new employer.

But Levandowski’s relationship with another autonomous tech start-up, Tyto Lidar, has been at the periphery of the case since it was filed. Tyto worked on early iterations of Uber’s LiDAR system, Waymo says. LiDAR—a laser-based radar that essentially allows an autonomous car to “see”—is crucial for making self-driving vehicles work and is at the core of the high-profile lawsuit.

Google has long suspected that Levandowksi had a stake in Tyto, that it believed he “was involved in competing side businesses, including enterprises known as ... Tyto Lidar.” Tyto was incorporated in August 2012, records show, and the company worked out of a building owned by Levandowski. Ognen Stojanovski, Levandowski’s friend, was listed as Tyto’s registered agent.

Levandowski has denied having a role in Tyto, but the filings on Thursday offer the most definitive statements from Waymo to date, claiming that he owned the start-up years before leaving Google. It’s unclear what evidence Waymo has of Levandowski’s alleged ownership. The filings say Waymo determined that was the case as a result of a response to a third-party subpoena. But it adds another layer to , preparing a lifeboat in the form of a startup.

“Waymo discovered on August 21 that Mr. Levandowski personally owned and controlled Tyto,” the company said. “Defendants failed to disclose Mr. Levandowski’s ownership of Tyto at any point during the discovery period, even though several of Defendants’ employees and shareholders knew of Mr. Levandowski’s relationship to Tyto and the related shell entities.”

Tyto’s path to Uber is complicated and involves a number of shell companies that were designed to hold the start-up’s patented autonomous tech, . Waymo said Thursday it was a herculean effort of uncovering one shell after another, saying it didn’t learn Levandowski’s role as the owner of Tyto until the final week of discovery, late last month.

“Due to the elaborate series of shell companies and trusts Mr. Levandowski set up to conceal his involvement in Tyto, Waymo was forced to serve more than a dozen subpoenas on a variety of entities ... to identify Mr. Levandowski at the center of Tyto’s ‘Russian nesting doll’ ownership structure.”

Waymo, Uber and Levandowski’s attorneys didn’t immediately respond to requests for comment

Initially, Tyto was incorporated as Odin Wave. The start-up first came on Google’s radar in mid-2013, Waymo previously said, after an engineer received a call about “a company named Odin Wave [that] had just submitted an order for a custom-fabricated part that was similar to a part used by Google in its unique and proprietary laser technology for self-driving vehicles.”

The employee, Pierre Droz, looked into Odin and found “several connections” between Levandowski and the start-up. In a deposition last month, Droz said he confronted Levandowski upon learning the connections. Levandowski denied any role, saying he didn’t have a relationship with the company.

In February 2014, the company changed its name to Tyto. Weeks later, records show, the company’s patents were transferred to a shell company called Pouch Holdings that also listed Stojanovski as its manager.

Waymo’s attorneys asked Levandowski about his personal connection to Tyto during an Aug. 22 deposition. The company suspects that Tyto’s name was changed to hide the business from Google. Similar to his previous deposition, Levandowski plead the Fifth.

Why did the name change from Odin Wave to Tyto Lidar?

On the advice and direction of my counsel, I respectfully decline to answer, and I assert the rights guaranteed to me under the Fifth Amendment to the Constitution of the United States.

Was it to obscure the existence of that business to Google?

...

: On the advice and direction of my counsel, I respectfully decline to answer, and I assert the rights guaranteed to me under the Fifth Amendment to the Constitution of the United States.

Sometime in 2015, Google says it considered purchasing Tyto and sent Levandowski to investigate whether it should buy the small company.

“Throughout this process, Levandowski never disclosed a relationship with Tyto and its employees,” Google previously said.

By the end of the year, Levandowski began discussing his job prospects with Uber. In early December, Uber , as Jalopnik first reported, months before Otto ever went public.

In Levandowski’s deposition, Waymo’s attorneys assert that a deal for Otto included the acquisition for Tyto.

“When Uber acquired Otto, part of the deal was for Otto to acquire Tyto Lidar, right?” an attorney asked Levandowski.

Again, he took the Fifth.