Most of these people are easy to track. It should be easy to
determine which of them could have been available to be at the scene
with Partridge. Also, it should be relatively easy (even after 5 months)
to determine which of them might have been free to visit Sophie or take out Patrick's happy memory etc. I am sure that Patrick used much of this public knowledge to narrow the list to the seven suspects.

This type of acalysis gets complicated if RJ is really just the leader of a consortium.
Which I think is probably the best guess. It explains why the finger
points in so many directions. In fact Brett might have been part of that
consortium. RJ took him out of the consortium because he was afraid of Brett Partridge (a bird). (RJ is afraid of birds).

I've got to go with Bertram as the leader, the true RJ (or at least a member of the consosrtium), because he basically says so to Jane. “When you get Red John in your sights I’ll be there”