The public dust-up between federal safety officials and Tesla escalated this week when the automaker left a fatal crash investigation—or was forced out.

Bloomberg reported Wednesday that the National Transportation Safety Board Chairman Robert Sumwalt called Tesla CEO Elon Musk to tell him that the automaker would be removed from an investigation surrounding a fatal crash in March that killed its driver, 38-year-old Walter Huang.

The report cites an anonymous source familiar with the phone call.

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Officials at Tesla refuted the report and said the automaker willingly withdrew from the investigation.

"Tesla withdrew from the party agreement with the NTSB because it requires that we not release information about Autopilot to the public, a requirement which we believe fundamentally affects public safety negatively," Bloomberg reported. "We believe in transparency, so an agreement that prevents public release of information for over a year is unacceptable."

On Thursday, Tesla further said "the characterization of the call as relayed to Bloomberg is false."

A representative from Tesla didn't immediately respond to questions from Green Car Reports.

Tesla Enhanced Autopilot

Tesla Enhanced Autopilot

The feud is another twist in the tragic crash and increasingly tempestuous investigation.

In March, Tesla appeared to publicly admonish Huang in a rare statement about the crash that it posted to its website.

"The driver had received several visual and one audible hands-on warning earlier in the drive and the driver’s hands were not detected on the wheel for six seconds prior to the collision. The driver had about five seconds and 150 meters of unobstructed view of the concrete divider with the crushed crash attenuator, but the vehicle logs show that no action was taken," the statement said.

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Musk has also publicly reprimanded journalists for not correctly reporting on its driver-assistance programs, going as far as nearly blaming the media for driver deaths.

"It's really incredibly irresponsible of any journalist with integrity to write any article that would lead people to believe autonomy is less safe, because people might turn it off and then die. I'm very upset by this," Musk said Wednesday during an earnings call.

Despite the public spat, Tesla likely will still provide information to the NTSB regarding the crash, although it may not be privy to prior notice of any findings.