The US Department of Justice (DOJ) is reportedly investigating an Uber data breach that took place in May last year.

Earlier this year, Uber revealed that an anonymous hacker managed to access the personal data of about 50,000 drivers.

The files containing the name and driver’s license number of some driver partners had been accessed.

Uber’s investigation found that a one-time unauthorised access to one of its database by a third party was occurred on 13 May 2014.

Reuters reported that an Internet address potentially associated with the breach was linked to Lyft chief technology officer Chris Lambert. In its latest report Reuters said sources familiar with the matter said that the DOJ will investigate whether Uber’s rival, Lyft, had any involvement in the breach while stressing that no-one had been accused of any wrong-doing.

Lyft released a statement saying, "We have not been contacted by the DOJ, U.S. Attorney’s office or any other state or federal government agency regarding any investigation."