Elon Musk says a Tesla Model X that crashed in Pennsylvania was not operating on Autopilot.

As an investigation into the first fatal crash involving an Autopilot-equipped Tesla Model S continues, the electric-car company had some good news to share on Thursday.

A separate crash - this one involving a Tesla Model X SUV in Pennsylvania - was not operating with the company's semi-autonomous driving technology activated.

CEO Elon Musk tweeted on Thursday that "onboard vehicle logs show Autopilot was turned off" in the Model X in question.

"Moreover, crash would not have occurred if it was on," Musk added.

Here's the tweet:

The July 1 crash was being investigated by the National Highway Traffic Safety Administration (NHTSA), according to a Reuters report earlier this month. It came shortly after the federal agency opened an inquiry into a separate crash that killed a driver in Florida. The driver involved in that incident in May was using Autopilot at the time of the crash.

Since then, the company has been on the defensive as road safety advocates called for Tesla to scale back the driving software, or be more explicit in its warnings about the technology.

Musk has insisted that Tesla vehicles are safer with Autopilot activated, citing millions of miles used during its internal testing of the technology.