Uber reportedly looked at data like social media profiles and credit card information (including whether the credit card was connected to a police credit union), when determining which people to Greyball.
The existence of the Greyball program was revealed in an article published in the New York Times on Friday, which attributed the information to four current and former Uber employees, who were not named.
Uber is using a tool called "Greyball" to work identify requests made by certain users and deny them service, according to Mike Isaac reporting for the New York Times.
To stymie those efforts, Uber served up a fake version of its app to make it appear the undercover regulators were summoning a vehicle, only to have the ride canceled.
Uber acknowledged it has used Greyball to counter regulators working with the company's opponents to entrap its drivers.
If a "Greyballed" official attempts to hail an Uber cab as part of a sting operation, the app would immediately cancel the ride hail. It was also used worldwide in Australia, China, Italy and South Korea.
The cat-and-mouse game with regulators is the latest example of the aggressive tactics that Uber has adopted while upending the heavily regulated taxi industry.
Among other things, the company has faced lawsuits for classifying its drivers as independent contractors to save money and allegedly stealing the technology for a fleet of autonomous cars that it is now testing.
But data collected through Uber's phone app has been used to identify officials monitoring its drivers.
The tool allowed Uber to show law enforcement officers images of "ghost" cars on the app or show that no cars were available for use, the paper said.
Ars has contacted Uber about Greyball but has not received a response.
A spokeswoman for Uber confirmed that Greyball was still in use, though on a much smaller scale than it once was.
The program recalls issues raised around Uber in the past, including statements made by SVP of Business Emil Michael at a dinner in 2014, which Uber CEO Travis Kalanick later apologized for, saying that Michael's suggestion Uber could essentially do opposition research on journalists were "terrible and do not represent the company". Oregon Live reported at the time that officials with the City Commissioner's office couldn't seem to book a ride, leading them to theorize that they'd already been blocked by the ride-haling provider. But in its early years Uber earned a reputation for exploiting legal uncertainty over whether its service should be regulated like taxis.