The ridesharing app Uber is making waves once again in Austin, this time as part of a federal investigation.

A city of Austin spokesman tells KVUE that the Department of Justice has contacted Austin Transportation and Aviation Department employees and told them they can expect subpoenas.

Our sister publication USA TODAY reports the agency is looking into the company's "ghost-app program" known as Greyball.

KVUE reached out to Uber for response to the investigation, they directed us to a blog post on their website about the technology, issued back in March.

The blog explains Greyball's intended usage, including testing new features by employees and to deter riders using the app in violation of the companies terms of service.

The post also says it began "prohibiting its use to target action by local regulators."

The New York Times first reported on the technology in March, claiming a code enforcement inspector in Portland, Oregon tried to hail an Uber car in a sting operation against the company. It claims some of the digital cars the inspector saw in the app did not represent actual vehicles, and others canceled their routes soon after.

The paper says that was because Uber used Greyball to tag the inspector as a city official "serving up a fake version of the app, populated with ghost cars, to evade capture."

The Department of Justice did not return our request for more information on the investigation.