It is interesting that this guy didn’t see anybody in front of him, but knows he was shot by police when he was standing next to Boyett. Boyett’s step son states almost immediately after the incident that he saw Boyett shot by a guy in Bandido colors.
Without knowing the bullet trajectory, it is difficult to state whether he is correct or not. In general, one might expect bullets traveling downward or not fired in the immediate vicinity to come from LEO weapons. If he was hit by rifle fire, then police are likely the shooter(s). There just isn’t enough data given to evaluate his claim and either confirm or deny it.