The trouble is...
JB's behaviour in the wake of the deaths may have been distasteful. It may have been irreverent. It may have been reaction to the shock. People react in some very strange ways sometimes.
Those behaviours and reactions alone are not enough to make him guilty.
When taken in a wider context, they do add something, but in isolation alone, they aren't enough.
It is only when Mugford tells her story, and we learn of him stealing money and 'disguising' a scene previously that we start to wonder.
Some of his interviews in the aftermath do not make for good reading either, but it is still very subjective.
For me, it is only when you revisit the entirety of events from the perspective of 'could JB have done it' that it becomes clearer that the weight of evidence points to him rather than Sheila.
Of course, not everybody shares my opinion, but my point being - nobody can convict him JUST for being arrogant, or aloof, or distant, or not grieving in a befitting manner etc.
