Solution—Con Gang Killer

First, let’s discover the front. He is not Somer (2) or Keeler or Carmody (3), hence the front is Oswald Munson. The front (Munson) is not the killer (4). The killer is not Somer (2 & 4) and we see in (5) that Keeler is not the murderer. Therefore, Dan Carmody is the man who killed Merrick.

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GO BACK; THE VIRTUE OF YOUR NAME IS NOT HERE PASSABLE.

—Shakespeare