The Justice Department is also looking into another Uber software program, named “Greyball,” which was used to evade law enforcement in cities where the company’s ride-hailing service was not allowed to operate. Separately, Uber is dealing with an inquiry over accusations that one of its employees bribed officials in India, and the company continues to be entangled in a legal battle over intellectual property theft with Waymo, a major competitor in the race to conquer self-driving car technology.

The “Hell” program was essentially a competitive intelligence initiative created by Uber to challenge Lyft for drivers and riders. According to the people familiar with the investigation, Uber employees used the program to monitor drivers who worked for both services. Uber would then use financial incentives to persuade drivers to work for Uber more frequently instead of Lyft.

The existence of the “Hell” program was uncovered this year by a technology news site, The Information, which said Uber ended the effort in 2016.

One key question, according to one of the people with knowledge of the investigation, is whether Uber engaged in some kind of unlawful computer access as part of its scheme.