silver

"Holy shit," I said. "How did they stop it?"
"They killed it," Bob said. "Here's where the silver bullets finally come in, Harry. Only a silver weapon can hurt a loup-garou, and not only that, the silver has to be inherited from a family member. Inherited silver bullets. "
"Really? Why would that work and not regular silver?"
"I don't make the laws of magic, Harry. I just know what they are and have an idea of when they're changing. That one hasn't changed. I think maybe it has something to do with the element of sacrifice. "
"Inherited silver," I mumbled. "Well. We'll just have to hope that this wasn't a loup-garou, I guess. "
"If it was a louper, you'd know," Bob said wisely. "In the middle of this town, you'd have a dozen people dead every time the full moon came around. What's going on?"

Fool Moon Chapter 8, Page 73-74