First of all ignore BOB's picture..

None of the remaining 5 suspects is RED JOHN instead everybody are involved in the TYGER TYGER group some how....and u'll get to know later that the TYGER TYGER organization and RJ are not in good terms .... So PJ throws a bait to RJ by getting all the TYGER TYGER masterminds in one room so that RJ would take advantage hence the BLAST ... But of course PJ saves them all thereby revealing RJ is some one out of the list.