When you think of serial killers, there are a few names that immediately come to mind: Ted Bundy, the Zodiac Killer and John Wayne Gacy, to name a few. But these American men only scratch the surface of the sheer number of violent, repeat offenders who are out there in the world, and many of those from other parts of the globe are often lesser-known. In today’s episode of Cold-Case Detective, we’ll be exploring two terrifying serial killers from Europe.