Uber has fired Anthony Levandowski, the former Google engineer who led Uber’s self-driving car efforts, because of his refusal to cooperate in the lawsuit filed by competitor Waymo.

Levandowski was at the center of a contentious lawsuit between Uber and Waymo over allegations documents he took were used in Uber’s self-driving car development. The news was first reported by the New York Times.  

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Earlier this month, Uber reached out to Levandowski in a letter, asking for him to cooperate in the investigation. As part of the request, Uber asked Levandowski either to confirm he never took documents from Google or return any remaining documents in his possession. If Levandowski failed to comply with the request, Uber said it would consider actions that could include firing him.

In its letter to Levandowski confirming his termination, the Washington Post reported Uber said it was justifying the firing for cause because of Levandowski's refusal to comply with the company’s legal requests. In particular, the letter cites Levandowski’s violation of a section saying he “returned or destroyed all property and confidential information belonging to any prior employer.”

Levandowski previously cited his Fifth Amendment right against self-incrimination and refused to cooperate significantly with investigators. Last month, Levandowski said he would step away voluntarily from Uber’s self-driving efforts, but a federal judge also moved to prohibit Levandowski from working with Uber for the duration of the case. Uber executive Eric Meyhofer, who took over Uber’s autonomous team when Levandowski stepped aside, will continue to lead the program.

In an email to employees Tuesday obtained by the Times, Angela Padilla, Uber's associate general counsel for employment and litigation, said Uber has emphasized the independence of its autonomous driving research during the case.

"Over the last few months Uber has provided significant evidence to the court to demonstrate that our self-driving technology has been built independently," Padilla said. "Over that same period, Uber has urged Anthony to fully cooperate in helping the court get to the facts and ultimately helping to prove our case."

While Uber has conceded Levandowski took documents when he left Google, the company has steadfastly denied any documents were in Uber’s possession or used for its self-driving car technology.

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The firing of Levandowski is also the latest stumble for Uber. The former Google engineer was a relatively high-profile acquisition for Uber — last year, Uber acquired Levandowski’s self-driving car startup Otto for $680 million and tapped him to lead the company’s autonomous driving research.

Autonomous driving has quickly become a high-profile area of investment and research for technology companies. Companies ranging from Uber to Apple have all invested heavily in research and planning for self-driving cars and many manufacturers see the field becoming the next ground changing innovation for many users.