Mafia 5. Seventeen Moments of Spring.

Kostyan, you didn't answer my reply.

Unfortunately, I can't answer the reply, but I'll try. 8)
You asked:

But if a regular soldier covered it up, wouldn't that be an unsuccessful murder? The idea is that there's a corpse and there should be two clues, as I understand it.

1. In this case, the murder is unsuccessful, and there can't be two clues.
1.1. No one forces the murderers to leave a second clue; there might not be one at all.
1.1.1. This is according to the rules.