Unless and until we know if there was anyone else involved, we don’t know for sure if he killed himself or someone else did.
Looking at the pictures I’ve seen, one lower body, with the 2 ARs, with his foot between the legs of the bipod (weird), and the second picture of upper body and head, with the revolver being up above his head, and his arms being straight along his body (weird) I don’t think he shot himself. What position was he in when he shot himself? Standing, ass on floor, laying all the way down? Pick one, and then look at the position of his body as well as the gun(s). The “ clean” shell casings in the blood, they weren’t kicked there.