The Aurora theater shooting stands as one of the deadliest mass casualty events in modern American history, carried out by a doctoral student with no prior criminal record against a crowd gathered for a midnight film premiere. Holmes wounded or killed 82 people in a matter of minutes, a scale of harm that shaped subsequent national debates about public safety, mental health, and the insanity defense. His trial — and the single juror's vote that kept him off death row — became a focal point for those questions.

Operating across three countries over nearly two decades, this French serial killer targeted victims with a consistency that allowed him to evade detection for years. The gap between confirmed killings and his own stated count — 23 documented versus roughly 150 claimed — reflects both the difficulty investigators faced in tracing his movements and the uncertainty that still surrounds the true scale of his crimes.