The National Highway Traffic Safety Administration opened an investigation into a fatal crash last Friday, multiple outlets reported, days after a Tesla driver who was allegedly using his car’s Autopilot feature slammed into a woman’s house, killing a 76-year-old grandmother.

A driver in Texas claimed he was using his Tesla’s autopilot feature when it crashed into a home at a high speed.

The NHTSA also opened a special crash investigation into the collision, the Wall Street Journal first reported on Monday, as the case remains under investigation by the Harris County Sheriff's Office.

The deadly crash took place in Katy, a Houston suburb, when the driver of a Tesla Model 3 left the roadway at a “high rate of speed” and slammed into a brick home, according to a report from the Harris County Sheriff’s Office.

The driver, identified in the report as Michael Butler, was cooperative and did not show signs of intoxication, and said he was using his car’s automated driving assistance program—the system Tesla calls Autopilot.