(Reuters) - The chairman of the National Transportation Safety Board and Tesla Inc Chief Executive Elon Musk had a “constructive conversation” on the agency’s probe into a fatal crash involving a Tesla vehicle that was operating in semi-autonomous Autopilot mode, the agency said on Monday.

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The NTSB on April 1 had said it was "unhappy" that luxury electric car maker Tesla TSLA.O had made public information about the crash of a Model X vehicle that killed the car's driver.

NTSB Chairman Robert Sumwalt “had what he described as a very constructive conversation with Mr. Musk over the weekend,” agency spokesman Peter Knudson said. “They discussed the investigation of the March 23 Tesla crash, NTSB investigative processes, and Tesla’s work to address the safety recommendations that were issued last year.”

A Tesla spokeswoman declined to comment.

The crash has put a sharp focus on Tesla’s Autopilot technology, which allows drivers to take their hands off the wheel for extended periods under certain conditions. Tesla requires users to agree to keep their hands on the wheel at all times before they can use Autopilot. Users, however, routinely brag they can use the system to drive hands-free.

Tesla said a week after the accident that vehicle logs showed no action had been taken by the driver right before the crash and that he had received earlier warnings to put his hands on the wheel.

The driver, who was 38, died at a nearby hospital shortly after the vehicle hit a concrete highway divider near Mountain View, in the San Francisco Bay Area. The mishap involved two other vehicles.

“The NTSB is looking into all aspects of this crash including the driver’s previous concerns about the Autopilot,” Christopher O’Neil, another NTSB spokesman, said on April 1.

Last month, the company said that a search of its service records did not “find anything suggesting that the customer ever complained to Tesla about the performance of Autopilot. There was a concern raised once about navigation not working correctly, but Autopilot’s performance is unrelated to navigation.”

On March 30, Tesla disclosed that shortly before the crash, the vehicle’s “Autopilot was engaged with the adaptive cruise control follow-distance set to minimum.”

Sumwalt last year said that “operational limitations” in the Tesla Model S played a “major role” in a May 2016 crash that killed a driver using Autopilot.

“System safeguards were lacking,” Sumwalt said in September. “Tesla allowed the driver to use the system outside of the environment for which it was designed and the system gave far too much leeway to the driver to divert his attention.”

The National Highway Traffic Safety Administration is also investigating last month’s crash. The two agencies are also probing a January crash of a Tesla that may have been in Autopilot mode and a fire truck.