The U.S. Department of Justice has launched a criminal investigation into Uber's use of Greyball, a secret software that worked to deceive authorities in areas where the ride-sharing service was banned or restricted.

Greyball helped Uber evade officials in cities where the company's service was not yet approved or regulated. The software identified and blocked rides to transportation regulators posing as Uber customers to prove the company was operating illegally.

The Greyball tool allowed the company to deploy what served as a fake version of its app to evade authorities.

The New York Times, which first revealed the software in March, reported Uber's legal team approved Greyball. After the initial report, Uber said it would prohibit employees from using the software.

The Justice Department's investigation into Uber was disclosed in a transportation audit issued by Portland, Ore., last week. Portland officials said the U.S. attorney's office for the U.S. Northern District of California notified them about the existence of an investigation into Uber.

Uber has faced a number of recent crises. In January, the company agreed to to pay $20 million to resolve federal charges that alleged the company misled potential drivers by overstating the incomes they can earn.

In February, former Uber engineer Susan Fowler Rigetti, in a blog post, described systemic sexism and sexual harassment at the company, which prompted an internal investigation led by former U.S. Attorney General Eric Holder.