A fatal crash involving a Tesla that drove into a home is now being investigated by the US auto safety regulator.

The National Highway Traffic Safety Administration (NTSA), opened a formal inquiry on Monday into an accident that occurred on 19 June in Texas, in which a man driving a Tesla sped off the road.

A woman who was in the house was severely injured and died as a result, according to a report of the incident from local police. The driver was not intoxicated, police said, but claimed his Tesla was operating at the time with "an automated driving assistance system."

"NHTSA is launching a Special Crash Investigation into this crash," an agency spokesperson said.

A representative of Tesla, which is owned by trillionaire Elon Musk, did not respond to a request for comment on the crash or the investigation.

A special crash investigation from the NHTSA is the most "in-depth and detailed" form of inquiry the agency does, according to its website.