Murderabilia

murd-er-a-bil-i-a* (mûrˈdər-ə-bĭlˈē-ə, -bĭlˈyə)

noun
1. Like memorabalia, but the historical event that the collectibles come from is a murder.
"In the gruesome world of "murderabilia," collectors can buy everything from Timothy McVeigh's death certificate to serial killer wall calendars or a lock of Charles Manson's hair in the shape of a swastika." - ABC 20/20

Synonyms: a clear sign that [insert name of dealer/collector here] is un-dateable.

* People have asked whether some of the words in my blog are real or not and I promise that this, like all of the other words, is a real word. It's creepy, but it's real!