There’s some controversy over the investigation of the fatal Tesla Model X accident that happened in Mountain View last month as both Tesla and the U.S. National Transportation Safety Board (NTSB) are now exchanging statements.

When first announcing its investigation, the NTSB said it couldn’t confirm whether or not Tesla’s Autopilot was activated during the crash, but it was also looking into other circumstances around the accident, like the subsequent battery fire.

After reviewing the data logs of the vehicle last week, Tesla issued a statement confirming that the Model X was on Autopilot and it released an explanation of the last moments before the impact.

Following the statement, the NTSB said this weekend that it was “unhappy” about Tesla releasing its interpretation of the data and it would now also look into the role of Autopilot in the accident.

Today, CEO Elon Musk justified Tesla’s statement in a tweet:

Lot of respect for NTSB, but NHTSA regulates cars, not NTSB, which is an advisory body. Tesla releases critical crash data affecting public safety immediately & always will. To do otherwise would be unsafe. — Elon Musk (@elonmusk) April 2, 2018

The agency already launched an investigation into Telsa’s Autopilot following a fatal accident in 2016 and it found that the driver assist system ‘functioned as designed’ but ‘played a role’ in the crash.

They are investigating the system again over an accident involving a Tesla Model S rear-ending a fire truck at a reported speed of 65 mph while the vehicle was on Autopilot, according to the driver.

It makes this new investigation NTSB’s third investigation into Tesla’s vehicles and the second currently ongoing investigation.

As previously mentioned, part of the investigation was about how to handle a battery fire after an electric vehicle crash.

Footage of the aftermath of the accident shows some battery cells explode – apparently before firefighters arrived on the scene:

As for the use of Autopilot, Tesla says that the driver ignored some alerts to hold the steering wheel during the drive.

Earlier today, we shared a video of another Tesla owner trying to recreate the situation that led to the accident and it gives a plausible explanation for what happened.

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