The family of NASCAR legend Jimmie Johnson is dealing with an unspeakable tragedy on Tuesday, as the parents and nephew of Johnson's wife, Chandra Johnson, are dead in a suspected murder-suicide.

According to police in Muskogee, Oklahoma, officers responded to an anonymous 911 call on Monday night about a woman with a gun and found 69-year-old Jack Janway dead from a gunshot wound. Officers then heard another gunshot and ultimately found 68-year-old Terry Janway and 11-year-old Dalton Janway dead as well.

Authorities believe that Terry, the mother of Jimmie Johnson’s wife, Chandra, was responsible for the murder of her husband and grandson before turning the gun on herself.

Jimmie Johnson, a seven-time NASCAR Cup Series Champion, married Chandra Janway in 2004, and the couple has two children. Chandra grew up in Muskogee, Oklahoma.

The Johnsons have yet to make a statement on the tragedy. However, ESPN is reporting that Jimmie Johnson will not race this weekend in NASCAR's Cup Series street race in Chicago. Legacy Motor Club, the NASCAR team Johnson drives for and co-owns released a statement on Tuesday saying Johnson and his family have “asked for privacy at this time and no further statements will be made.”

Jimmie Johnson, 47, started offroad racing when he was just four years old and made his NASCAR Busch Series (now Xfinity Series) debut at 22 years old. His first full season competing in the NASCAR Cup series was in 2002, and he won his first championship in 2006, as well as the next four consecutive titles.

Only the iconic Richard Petty and Dale Earnhardt have as many NASCAR Cup Series championships as Johnson. The grieving legend also has won two Daytona 500s, four Coca-Cola 600s, and four Brickyard 400s.