NASCAR racer Jimmie Johnson’s in-laws were found dead in what Oklahoma police are investigating as a murder-suicide on Monday.

Muskogee police told TMZ that Jack and Terry Janway, parents of Johnson’s wife Chandra, and 11-year-old nephew Dalton Janway were found dead at the scene.

Law enforcement officials consider Terry a suspect, per TMZ and Fox 23, though the incident is under investigation with no known motive.

Officials found a body in a hallway of the home upon arrival and then heard another gunshot coming from inside the house.

A 911 call made by an unidentified woman alerted authorities to someone with a gun at the home before hanging up the phone.

Johnson, a seven-time NASACAR Cup champion, is schedule to race in a Chicago street event this weekend.

He and Chandra were married in 2004 and have two daughters.