- Elementary, my dear Watson! The culprit sent a boy a grim message, encoded with the substitution cipher, just like in the "Dancing men" story. But, as we have too little of statistical information, we'll have to check for context.
First of all, look at the 3rd word, Watson. It's of form 1233 - not too much to guess here, a poll, roll, wuss or something will do. But if I assume the message says something grim - what would you expect to see in there?
- Erm... "kill"?
- Sure Watson, but even if it was it, we'd still need a necessary "will" before it.
- Oh! So "will" it is.
- Let me see the next word here - it must be a verb then. So "WILL _I_" and I don't believe it's the word "TIE" that we would see in a creepy-pasta like this.
- So... my god, is it "Will die"?! But who, Holmes?
- Patience. Whoever it is, he might already be dead, since it's been over 18 years since. Yet... - Sherlock looks into the memo intensely - it certainly is Grandma (or grandpa, but he wasn't mentioned in the post). Just look at the pattern of the previous word.
- Now it's all clear.
- Not all, Watson. But the data is plentiful.
Sherlock wrote down everything he could deduce by now:
___R GRANDMA WILL DIE __N _EAR_ _EN_E
- That... That's not enough, Sherlock. I suppose, we can't solve it with just one lame message.
- Oh, quite the contrary - Sherlock smiled. - I only started. Look at this chart, - he started scribbling the chart, then laughed halfways and made another one, better.
- This is what we deciphered so far, place in grid represents the square - dark, light, with or without dot. What can you tell so far?
- One of them contains alphabet. Probably the other should too, but...
- But I made a mistake paying attention to the tone of the square. Just looking at the dot gives us exactly 26 positions. Also, let's write the alphabet in the first.
- A-a-and, judging by all that, we get:
___R GRANDMA WILL DIE _EN _EAR_ HENCE
- Ok, now I get it. It's "Your grandma will die ten years hence". Hell of a threat here.
- Actually, if I understood the cipher correctly, it's also written with mistakes. See for yourself:
- So is she still alive?
- Who knows, my friend, who knows. She was, like, 90 in that year. If she actually lived till 2009th, that culprit has rather prolonged her natural lifespan, than did any harm. Given he actually answered for his words.