While my little RJ investigation i found William blakes painting called "a brace of partridge". There are two partridges shown and thats why i thought for a short moment: can there be a Brother of Brett partridge who wie know with another Name? Thats maybe the reason why partridge has that Similarities to RJ (his brother) and why heller makes it a Kind of obvious.
Kept that unlikely thought in mind i was looking all Old episodes with the 30 cbs suspects. And i discovered something interesting. Watch the Episode with royston Daniel and wait for the scene when Jane is in Daniels Office. He grabs a Book with a picture of Daniel on it. And incidentally he says something like: "its a very old picture of you, isnt it?" stop that scene and compare that picture with One if partrdige. Ouh i think Dr. ROYston Daniel is RJ!
Wish you a Good Time and an succesfully search for red john. Sorry for my poor english