None, as far as I can tell.
No fingerprints, no DNA, no gunshot residue. No video from the missing camera. No third shell casing, or any bullets whatsoever. No search of the other two vehicles and trailer owned by RG at the scene. All courtesy of the local police department.
The testimony of the ear witness was not consistent with the testimony of the two eyewitnesses, whose testimony was not consistent with each other. Even after they had 2 1/2 years to work on it.
There is no physical evidence to prove the LK/RG version is more likely than the version involving a struggle with the gun.
To me, if you have two equally plausible versions, separated only by the word of two people who demonstrated under oath on the witness stand that they are drug users and liars, along with their stated intention to “ruin the life” of the other person, that’s reasonable doubt.