Uber Technologies Inc. is being investigated by the Department of Justice for using a software tool, which let its drivers evade local transportation officials, Reuters reported Thursday.

The ride-hailing company has already acknowledged the existence of the software tool, known as ‘Greyball’ and its use to ply in the areas where its services hadn’t been approved such as Portland, Oregon, the report added.

Read: What Is Greyball? Uber Used Data Collection Tools To Avoid Authorities And Operate Illegally: Report

The issue came to light in a New York Times report published in March, which revealed details about the software. The tool would not only let Uber operate in areas it wasn’t allowed in, but would also populate the app with spoof cars to fool the authorities, while actual drivers on the road would continue to operate and avoid being reprimanded.

The company was deeply involved with the use of the tool, according to the report — the tool is said to have been approved by its legal team and was being constantly monitored by the company's regional general managers.

Greyball isn’t the only tool of its kind used by Uber— the company has used technologies such as a geofencing technique, which would create a virtual perimeter around the offices of law enforcement agencies, so as to keep drivers away from those areas. Furthermore, the app collected data of users who frequently opened and closed the app, which it believed to be government officials. The company even visited electronics stores to get its hands on phones used by law enforcement officials, so as to stay ahead of any potential investigators.

Shortly after its use of the tool to evade authorities became public, the company prohibited the use of Greyball.

Uber has declined to comment on the issue, but its lawyers have reportedly told Portland authorities that the Greyball technology was “used sparingly” in the areas where Uber’s services weren’t approved.

Greyball was a part of a larger program called “violation of terms of service” (VTOS), which included the analysis of users’ credit cards, devices, location data and other such data. The company had stated in a blog post that the technology was being used for detecting frauds and protecting drivers from harm, but its fate and the final analysis of how and why the tool was used would only be revealed post a formal investigation since the usage of the data derived using the program, including customer’s credit card data is not yet known. According to the report, the data might have been used to check which credit union the potential riders were affiliated with, and matching it to their social media profiles to find out whether they were law enforcement officials or not.

Read: Uber Greyball News: Company To Review Program, Stop Targeting Regulators

The criminal investigation could potentially make things worse for the ride-hailing company, which has been suffering from a barrage of issues lately including complaints about a sexist work culture and underpaying drivers.