A federal agency is investigating a fatal Tesla crash in California, but hasn't said whether the Model 3 car was using Autopilot

• The NHTSA has begun investigating a California Tesla crash that killed the driver and injured two.
• The agency didn't say if the Tesla Model 3 was operating under either Autopilot or Full Self-Driving, Reuters reported.
• NHTSA told Reuters it previously had 28 probes into Tesla crashes, with 24 still under investigation.

The US vehicle safety agency on Wednesday said it was opening a probe into a fatal Tesla crash in California that killed the driver on May 5, according to a Reuters report.

The Model 3 Tesla crashed into an overturned truck on a highway near Fontana, California, injuring the truck driver and a motorist who had pulled over to help. The Tesla driver was pronounced dead at the scene.

The National Highway Traffic Safety Administration (NHTSA) didn't say whether the Tesla was operating under Autopilot - Tesla's driver-assist software - when the crash happened, Reuters reported.

NHTSA told Reuters it previously had 28 probes into Tesla crashes, with 24 still under investigation.

Insider contacted the NHTSA for comment, but did not immediately receive a response. An agency spokesperson told CNBC it has "launched a Special Crash Investigation for this crash."

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"NHTSA remains vigilant in overseeing the safety of all motor vehicles and equipment, including automated technologies, and leverages SCI where appropriate," the spokesperson added.

At least three Tesla drivers have died while the car was operating under Autopilot. The National Transportation Safety Board has called for more scrutiny over the driver-assisting software.

Tesla didn't immediately respond to Insider's request for comment.

The driver of the Model 3 was 35-year-old Steven Michael Hendrickson from Running Springs, California, according to a San Bernardino County Coroner's office report. The California Highway Patrol is also investigating the crash, it said.

Tesla's Autopilot is the company's standard driver-assistance system that enables cars to stay in their lane and keep up with highway traffic using cameras and sensors. Full-self-driving, which is a $10,000 add-on option, builds on Autopilot with self-parking, and traffic light, stop sign, and highway recognition.