In a small inn (the more remote the better), a man turns up dead. There are no wounds on his body what-so-ever, and he aboslutely reeks of garlic.
The man died of a curse that forced him to eat a clove of garlic a day or suffer the penalty. This gets really interesting if the body somehow appears on top of a someone the villagers are suspcious of.
Held in a lead sheath the blade of this sword is tipped with uranium and any wound from it, even a tiny one, will go cancerous, although the effects may not show up for months or even years.