1) Who writes the word "Building" on a separate address line and without abbreviating it? A foreigner who mistakenly thinks the word "Building" is important on an address line. Americans would write "Bl" or "Bldg" on the same line, if necessary squeezed on at the very end, not going to a second line.
2) Who puts a period after "Ave" (or "St" or "Rd")?? I don't.
3) I have a degree in foreign languages and the English used in the letters sounds to me like a foreigner trying to think in English. The person "knows" the meaning of the words, but doesn't realize how stilted the English sounds to a native English speaker. For language students, it's often a laborious process trying to translate simple concepts into a language not his own. The non-native speaker might think "You die now" expresses the thought such as "You're going to die" or "Die, you suckers" or "You're going to die ha ha", which may have been what he was thinking as he wrote "You die now".
4) A computer user who does inputting as part of his job would be used to writing the date with six digits. I have to input the date this way in my job, and it's therefore second nature to write six digit dates on checks, etc.
On the other hand, I think this phrase sounds like a weak attempt to sound foreign.