Alphabet Incs Waymo self-driving car unit sued Uber Technologies and its autonomous trucking subsidiary Otto on Thursday over allegations of theft of its confidential and proprietary sensor technology.

Waymo accused Uber and Otto, acquired by the ride services company in August, with stealing confidential information on Waymos Lidar sensor technology to help speed its own efforts in autonomous technology.

Ubers LiDAR technology is actually Waymos LiDAR technology, said Waymos complaint in the Northern District of California.

Uber said it took the allegations made against Otto and Uber employees seriously and we will review this matter carefully.

Lidar, which uses light pulses reflected off objects to gauge their position on or near the road, is a crucial component of autonomous driving systems. Previous systems have been prohibitively expensive and Waymo sought to design one over 90 percent cheaper, making its Lidar technology among the companys most valuable assets, Waymo said.