They found his cell phone still in his hands and his head in the back seat.
Madness string 9611
To preface this, chicken and human rigor mortis is roughly the same. For a chicken if you slaughter the chicken and want to eat it, you have less than 1 hour to get the chicken in the pot before rigor mortis, else you have to wait 8hours. The normal amount of time recommended is 3-5 days in the fridge to let the body relax. For humans it's 2 hours till rigor mortis then 8 hours and most likely another 12 hours of rigor mortis.