This one is stupid
It's important that he's pinged as a townie before his first kill, he can keep quiet, don't use his skill, until he gathers info about the roled townies, and use them to find out the vampire, and before all the vampire gets killed, then he can show his fangs! It is not gonna be easy or gonna work like that, but at least he has a more chances of being undetected. Besides he's working alone, he's not as powerful as the mafia spy.All the more reason to have them show up as the WH, and not a townie, at the beginning. Though the chance of the WH being pinged on the first night, and not having killed the first night, seems so low that I also consider making them seem a townie before a kill does not seem worth it.