This is my entry for Crosshare's March Midi Contest. Good luck solving the mystery, er, meta!
Hint 1: As Sherlock Holmes would say, finding the weapon and location is elementary. The killer, however, not so much...
Hint 2: According to 34A, the killer is hiding somewhere in the grid.
Hint 3: What's up with that cryptically-worded clue at 11A? I don't think the killer is a fisherman.
Hint 4: Oh, "angled" as in "diagonal"!
Hint 5: And a corner-to-corner grid-spanner at that!