Officers arrived at the home of Jack and Terry Janway on 26 June after receiving a 911 just after 9pm from a female caller saying there was “a woman with a gun” at the address.
Footage released to TMZ shows the officers approach the front door of the Suroya St address with their handguns drawn.
The Muskogee Police Department officers observe a body — later confirmed to be 69-year-old Jack Janway — under a blanket in the hallway.
As they call out, a single shot can be heard inside the house.
Spokeswoman Lynn Hamlin previously told The Independent they believed Terry, 68, shot dead her husband and 11-year-old grandson Dalton before turning the gun on herself as officers arrived.
Johnson, who is married to the Janways’ daughter Chandra, pulled out of a NASCAR street car race in Chicago after the shooting. He is yet to comment publicly about the family tragedy.
While police are yet to reveal a possible motive, Terry Janway had reportedly suffered from depression after losing her son Jordan Janway in a skydiving accident in San Diego in 2014.
Chandra’s sister Marianne “MJ” Janway wrote a heart-breaking message on Facebook on the day after the shootings.
“Please tell me this isn’t really happening please god someone,” she wrote.
Jack Janway was a respected therapist who ran the Janway Chiropractic & Acupuncture Clinic in Muskogee.
On social media, friends, family and patients paid tribute to Jack as a devoted family man, Christian and healer.
Johnson, 47, is a seven-time NASCAR Cup Series champion who has won the Daytona 500 twice.