I am not sure I agree that JK was there during the shooting as I don’t think he would have had time to skedaddle before the first officer arrived. (Wasn’t that officer just down the road and arrived within minutes of the 911 call?) And JK wouldn’t have fled the scene - he would have tried to render aid to LK.
But I can totally see that he might have arrived on scene after the incident and was one of the 40-50 people milling around and tramping through the crime scene. And may possibly have been able to “influence” LE regarding the crime scene investigation - which might explain why some of those officers seemed to be squirming a bit on the witness stand.