It seems that frustrated drivers aren’t the only ones picking a fight with Uber CEO Travis Kalanick. And this time dropping a four-letter explanation and huffing away isn’t going to end the argument.

Last week Waymo, Google’s self-driving vehicle division, filed a lawsuit against Uber, accusing it of pilfering up to 14,000 proprietary files related to self-driving vehicle technology.

The suit revolves around Anthony Levandowski’s departure from Google last summer to run Otto – a company that was purchased by Uber from Google last year for $680 million. The company is focused on developing self-driving trucks.

The suit alleges that Levandowski downloaded files related to the LiDAR navigation system before heading to Otto.

LiDAR (which stands for light detection and ranging) uses lasers to generate a 3D map of the surrounding environment so autonomous vehicles can “see” where they’re going. Waymo claims that Otto’s version of LiDAR is too similar to theirs to be coincidence.

This assessment was reached after engineers at Waymo were inadvertently copied on an email from a component supplier working with Uber. These emails allegedly contained drawings that showcased the use and placement of 3-D sensors considered trade secrets of Google’s parent company Alphabet.

Uber, which is currently valued at about $70 billion, is calling the suit baseless. However, because it was filed under the Defend Trade Secrets Act, a federal law designed to protect U.S. companies from foreign IP theft, Uber needs to be careful.

The way this law is written, Waymo can ask the court to shut down Uber’s self-driving experiments and confiscate any associated tech until a ruling is reached. So Uber’s driverless developments would be dead in the water. Waymo is yet to make those requests.

Aside from the financial ramifications of a judgement in favor of Waymo, Uber could also be exposed to criminal charges for stealing trade secrets. If Uber or Otto execs are found guilty of even knowing about illegal activities, they could face as much as ten years in federal prison.

And making any upcoming calls or meetings just a little more awkward - Google has a $250 million investment in Uber.