The government will close its investigation into the first Tesla Autopilot fatality

The National Highway Traffic Safety Administration is expected to close a six-month investigation into the first Tesla Autopilot fatality without seeking a recall, according to a source briefed on the matter.

The auto safety agency did not find evidence of a defect that would have required a safety recall of the cars, the source said.

NHTSA will hold a press conference at 12 p.m. ET regarding the Tesla investigation.

Tesla's Autopilot, introduced in October 2015, has been the focus of intense scrutiny since it was revealed in July that a Tesla Model S driver, Joshua Brown, was killed while using the technology in a May 7 collision with a truck in Florida.

Brown was driving his 2015 Model S in Williston, Florida when a truck made a left turn in front of the car. The Model S then passed under the truck, with the bottom of the trailer striking the windshield. The Tesla then drove off the road and smashed through two fences before hitting a power pole.

Tesla wrote in a blog post at the time that the Autopilot system did not notice "the white side of the tractor trailer against a brightly lit sky, so the brake was not applied."

Brown's death was the first known Autopilot

Tesla in September unveiled improvements to its Autopilot software, adding new limits on hands-off driving and other improvements that CEO Elon Musk has said likely would have prevented a fatality in May.

This story is developing.