Uh oh… did he kill someone else instead?
LoA

Ah, there’s the mystery for others to find out.
I’ll give you all a hint using a simple replacement cypher:
Fkdj Sehgao Xkkpd
I love encryption puzzles. :D

Well, since no one seems to be catching it:
Dealey Plaza.
Dallas, Texas.
Three shots.
The hint: John Wilkes Booth.
Instead of killing his intended target, his shots passed through a ripple in time, killing John F. Kennedy.