You honestly think that Jeremy would languish in prison while DB had freedom? I think had that been the case he'd have grassed him up and made him take the same punishment and would probably be out now.
Let's just suppose it was Jeremy and DB regardless of who pulled the trigger(s) and which gun(s) were used.
Jeremy would know full well that if he dobbed DB in, he himself would never get out.
As it is, if Jeremy maintains innocence and it is shown to be a completely unsafe conviction, then all those people that have grabbed WHF and the cash will have to get out and repay the inheritances.
That IMO is why they are in fear and dread Jeremy's release.