A post on a previous thread suggested the repeated references to “47” might relate to “Agent 47” from the “Hitman” video game. FWIW, one of the photos of the perpetrator also shows him dressed like the “Agent 47” character...
The Daily Mail article states he was obsessed with the number 47, and even has a picture of his car with a large “47” painted on its side.
If you look at that stupid symbol that he has showing up all over some of his video’s, you can trace ‘4’s and ‘stylized ‘7’s in its structure.
(“Agent 47”)
Maybe it was ND47 from a movie?
Forgot the movie