The Justice Department is probing allegations that Uber used phony software to thwart city officials looking at whether the ride-hailing company was following local regulations.
The city of Portland, Oregon, said in an April audit report that it was notified of the federal inquiry by the U.S. Attorney’s Office in San Francisco. Portland says it is cooperating. Uber and the U.S. Attorney’s Office both declined to comment.
Reuters and other news outlets have reported that the investigation is a criminal probe currently before a grand jury.

Uber’s software—nicknamed “Greyball”—identified regulators who posed as riders while trying to collect evidence that Uber’s service was breaking taxi laws. Uber allegedly served up a fake version of its app to make it appear the undercover regulators were summoning a car, only to have the ride canceled.
Portland officials began investigating Uber after the New York Times disclosed the existence of Greyball in March. “The city of Portland was notified by the United States Attorney of the Northern District of California that Uber is the subject of a federal inquiry,” the audit report stated.