G_T_G
Since the gun was so close to both of them, would both of them test positive for nitrate residue?
TIA
If fired at near contact range I would expect that both would test positive. The positive result is not as important as the location that the nitrate was found. Zimmerman would test positive on the hand that held the gun, Martin would have a burn pattern around the entry wound. If Martin were wrestling for the gun when it went off the forearm and hand that held the slide would test positive as well as the entry wound. A struggle for the pistol is about the only way to explain the empty shell casing in the gun's chamber and a full magazine.
Regards,
GtG