Tesla is currently under investigation in the United States for the carmaker’s claims that its electric vehicles are able to drive themselves, according to sources cited by Reuters.

A previously-undisclosed probe was launched by the US department of justice following a string of over a dozen crashes, including some resulting in fatalities which involved the use of Tesla’s Autopilot which was active when the crashes occurred, sources to the news wire were quoted as saying.

More recently, Tesla CEO Elon Musk was reported as saying on a call that the electric carmaker will soon be releasing an upgraded version of its Full Self-Driving assisting driving software that would enables drivers of the cars to travel to “your work, your friend’s house, to the grocery store without touching the wheel,” Reuters reported.

Tesla states on its website that “Autopilot is a hands-on driver assistance system that is intended to be used only with a fully attentive driver. It does not turn a Tesla into a self-driving car nor does it make a car autonomous,” and that the driver must agree to always maintain control and responsibility of the vehicle.

Such warnings could complicate any case the justice department might want to bring, the sources to Reuters said. Federal and California safety regulators have started their scrutiny of the claims about Autopilot capabilities and whether or not the system’s design gives customers a false sense of security, which could induce them into treating the Tesla vehicles as driverless cars and become complacent with safety.

Also part of the latest probe, justice department prosecutors in Washington and San Francisco are examining whether or not Tesla misled customers, investors and regulators with unsupported claims about its driver assistance technologies. Possible courses of action by official conducting the inquiry could include the pursuit of criminal charges, civil sanctions or close the probe with no further action, the sources added.

The US national highway traffic safety administration (NHTSA) opened investigations into a series of crashes – one fatal – involving Teslas operating on Autopilot crashing into parked emergency vehicles. NHTSA official stepped up the probe in June to cover 830,000 Teslas with Autopilot, which identified 16 crashes involving the EVs and stationary first-responder and road maintenance vehicles.

In July, the California department of motor vehicles accused Tesla of false advertising with regard to Autopilot and Full Self-Driving capabilities as offering autonomous vehicle operation. The carmaker subsequently filed papers with the agency, seeking a hearing on the allegations and the carmaker intends to defend against the allegations. The California DMV stated that it is currently in the discovery stage of the proceeding, Reuters reported.