The National Highway Traffic Safety Administration (NHTSA) last June opened an investigation into an accident involving a Tesla Model S in which the sole occupant of the vehicle was killed. On Thursday, the NHTSA said it did not find a safety-related defect and closed the investigation.

On May 7, 2016, Joshua Brown’s Tesla Model S crashed into the side of a tractor trailer as it was crossing the road. Data from the vehicle showed that it was being operated in Autopilot mode although the Automatic Emergency Braking (AEB) system never provided a warning and didn’t kick in.

What’s more, the driver never attempted to brake, steer or otherwise avoid the collision. The last recorded action from the driver took place less than two minutes before the crash when he increased the cruise control speed to 74 mph. Conditions that day were clear and dry.

NHTSA’s crash investigation team determined that the tractor trailer should have been visible to the driver for at least seven seconds before impact.

In conclusion, the NHTSA said it was unable to find a safety-related defect and that further examination of the issue doesn’t appear to be warranted. As such, the investigation has closed.

A spokesperson for Tesla told The Verge that the safety of their customers comes first and that they appreciate both the thoroughness of the NHTSA report and its conclusion.