NTSB reveals distressing message passenger sent before NASCAR star Greg Biffle's fatal plane crash

"We do not know the circumstances which led the aircraft… to attempt to return to the airport, but that is the focus of our investigation," he began.

Graham was asked at Friday's initial press conference about a reported text sent from Biffle's wife, Cristina Grossu Biffle, to her mother in which she texted, "We're in trouble."

At the time, Graham said he was unaware of the message but on Saturday, he confirmed that one unnamed passenger did send a distressing message. 

"This morning, I can confirm that the NTSB is aware of one brief text from a passenger aboard the aircraft to a family member that read, 'Emergency landing.'" 

Graham added, "We are not aware of any other communications from passengers onboard the aircraft to those on the ground." ]

Biffle, 55, was killed alongside his wife, Cristina, and children Ryder, 5, and Emma, 14. Three other people killed onboard were identified as Dennis Dutton, his son Jack, and Craig Wadsworth.

The plane crashed roughly 10 minutes after departure.

According to Graham, three people aboard the Cessna C550 were licensed pilots, but officials were not able to verify as of Friday who was piloting the flight. He added Saturday that that information was still unknown. 

He also noted Saturday that early witness accounts did not point to any apparent issues with the plane.

"Early indications from multiple sources indicate that the airplane was stable on approach, configured for landing with the landing lights on, but the aircraft was coming low."