Uber acknowledged hiring a former Google engineer -now accused of stealing self-driving car technology -despite having received warnings that he was still carrying around some of his former employer's property.

The admission, contained in a court filing, is the latest twist in a high-profile legal fight between the ride-hailing company and a Google spin-off, Waymo. Both companies are battling to build self-driving cars that could reshape the way people travel.

Waymo alleges that Anthony Levandowski, the former Google engineer at the crux of the case, ripped off its trade secrets before departing in January 2016 to found a robotic vehicle startup that Uber acquired seven months later. The lawsuit maintains that Uber then transplanted the intellectual property allegedly stolen by Levandowski into its own fleet of self-driving vehicles -a charge that Uber has adamantly denied since Waymo filed its complaint in federal court four months ago.

In May, U.S. District Judge William Alsup ordered Uber to return the stolen files, writing that evidence indicated the company "knew or should have known that he possessed over 14,000 confidential Waymo files."