Michael Donovan Avin reportedly was arrested for threatening to bomb Darlington Raceway, per Alex Andrejev of the Charlotte Observer.
According to the arrest warrant obtained by Andrejev, Avin was charged with possession, threatened or attempted use of a weapon of mass destruction for an act of terrorism after leaving phone messages at the track "describing a possible explosive device and the results it may create to further his cause."
Investigators at the Darlington County Sheriff's Office also said Avin wrote a letter to another location revealing he had access to 125 tons of materials that could be used in creating a bomb.
NASCAR is scheduled to return Sunday at Darlington Raceway for its first event since it went on hiatus because of the COVID-19 pandemic.
The last completed NASCAR event was the FanShield 500 in Phoenix on March 8.
It, along with so many other sports across the United States, has been suspended since March because of concerns about the coronavirus. There will be two NASCAR Cup Series races at Darlington Raceway in the immediate future with one on Sunday and one next Wednesday.
The organization then shifts its attention to the Coca-Cola 600 at Charlotte Motor Speedway on May 24.
As for Avin, WCNC Charlotte reported he is awaiting a bond hearing in jail while the case remains under investigation.