NASCAR fans were stunned to learn this week that the mother-in-law of racing star Jimmie Johnson appears to have killed her husband and grandson in a murder-suicide. 

According to Fox News, police in Muskogee, Oklahoma released a statement explaining that three individuals who had been fatally shot were found in a home on Monday evening.

NASCAR "saddened by the tragic deaths"

Officers from the Muskogee Police Department entered the residence after a 911 caller reported a disturbance and seeing someone with a gun at 9:05 p.m.

Inside they found the bodies of 69-year-old Jack Janway, 68-year-old Terry Janway, as well as that of their 11-year-old grandson. The couple were the parents of Jimmie Johnson's wife, Chandra Janway, and the child was her nephew.

The statement said authorities believe that Terry Janway murdered her husband and grandson before finally turning the weapon on herself.

E! News reported that NASCAR provided it with a statement that read, "We are saddened by the tragic deaths of members of Chandra Johnson's family."

Mayor calls killing of grandson "bone-chilling"

"The entire NASCAR family extends its deepest support and condolences during this difficult time to Chandra, Jimmie and the entire Johnson and Janway families," it added.

Jimmie Johnson is withdrawing his car from the upcoming NASCAR event amid his family's heartbreaking tragedy. pic.twitter.com/IuHmwv20yl

— E! News (@enews) June 28, 2023

Muskogee Mayor Marlon Coleman told Fox 23, "It was traumatizing to find out that a long-standing family who had made so many contributions to our community were involved in this type of incident."

"It was even more bone-chilling to find out there was a child involved," he stressed. "I knew Dr. Janway. Dr Janway has worked on me, we've been acquaintances for a very, very long time since I've been in Muskogee. Just knowing that it was him and his family took a different toll on me."

Johnson withdrawing from race

Legacy Motor Club is Johnson's racing team, and it released a statement announcing that he would be withdrawing from an upcoming race in Chicago following the tragedy.

LEGACY MOTOR CLUB has elected to withdraw the No. 84 Carvana Chevrolet from this weekend’s NASCAR Cup Series event in Chicago.

The Johnson family has asked for privacy at this time and no further statements will be made

— LEGACY MOTOR CLUB (@LegacyMotorclub) June 27, 2023

While Johnson as yet to post about the death of his in-laws, fans offered messages of support on an unrelated post that he had earlier retweeted.

So sorry about this horrible occurrence. Thoughts and prayers for your family.

— DMAZ (@Debmcaz) June 28, 2023