Hello arcovk
I have reviewed the attached demo and my conclusion is that this situation is more of "on the spot" handling, meaning that the player should have received a light punishment. The reported player did exactly the same thing as an edger or a player/s that shoot zombies into humans.
When you see this kind of players my advice is to hold your ground and defense. Be prepared to shoot and corner that human once it turns into a zombie.
I will not issue a punishment, but if the player continues with this kind of gameplay then it will receive a ban.