'Z` exists, and is a source of much insight into the anomalies and contradictions in this case...
Remember...
That ballistic expert Fletcher said he could not say whether or not any of the 25 bullets had been fired through a silencer, yet there is what appears to be a mark made by the silencer, around the lower non fatal entry wound, whist at the same time, there is a marked absence of the same, around the upper entry wound beneath the chin...
Silencer appears to have been used at time first shot was fired, yet absent when second shot was fired...
If none of the 25 bullets had been fired through the silencer, it paves the way for an air rifle to have fired at least one of the original bullets,,.