The Riddler answers

  • CONUNDRUM ANSWER

    Brad is a priest (Father).
  • BLOOD TIES ANSWER

    Harry & Joe are brothers. Alex is Joe's wife and Frank is their (adult) son
  • WHO KILLED MR. BLUE ANSWER

    Mr. Green lunged for the ax and threw it at Mr. Blue, who was trying to exit through the door. (Mr. Green could see what he was doing because of the lightning.)