In the calm and peaceful Rurdem Town, a series of murders is driving the local police crazy. The police suspects this to be the deeds of a serial killer. They are right about that: the arrogant psycho got borred after the seventh murder, and decided to challenge them. He left behind a note that contain clues about his identity. But the jerk encrypted it. The police, frustrated, decided to set up a big bounty to whomever decipher the note and identify this serial killer.
The note left by the serial killer:
Decipher this and you'll know my name: 87E95 116M120 149W169 19D24 74X91 1R14 7Z30 10L27 135W153 102P111 101Q113 141Q159 27P40 25O37 35U51 75F82 43K49 2Y20 10A18 4W22 59S71 122B143 107N122 104V123 52V69 127L130 137L142 59R68 56M64 67J74 120C144 30N41 109W125 121J126 76D99 56U74 108R127 8Q30 5Y21 3R16 79L84 91H116 52W68 84Q96 125K133 11X28 22V37 75U93 4I8 126J133 8Z25 10D15 10C30 138P151 22W40 39Q47 56A78 95L110 9B34 69O79 135F138 I'll leave hints with each victim I kill next.
Note: The story is not necessary to solve the puzzle. You can skip it if you want.
Hint #1:
Subtraction is needed.
Hint #2:
If you give up, you'll never know who I am. (notice the added tag)
Hint #3:
34O44 127W127 56H59 15P34 119K125 19C25 40P51 35B40 146V163 53M69 146N155 79B84 80N91 24D29 124D125 59F68 94O106 34G40 34F41 8J15 78M92 130J133 85C89 138L143 106P125 110H111 33A37 34W50 71F82 126R137 45K61 8U24 85J100 118D141 31V32 148J151 110D115 69W85 39J54 73H74 130F139 115D138 65L80 21H26 22C28 140G140
Hint #4:
44U60 48M64 42O52 119C125 13N22 114D119 39V56 33R54 36G38 128P147 83T100 87B92 101P114 103L118 61Q73 74Q96 147H150 85L102 60M70 130K142 149P162 78U102 46U64 42F51 136H137 69P90 143C167 84J99 78F81 82L101 64B89 60Q82 96U114 83B90 116T131 28M42