Season 4 - Episode Guide

London, 1888. The city is gripped by a string of murders, each more gruesome than the last. Experts delve into one of history's most notorious mysteries.

Amanda Antoni's husband finds her body in their basement with blood everywhere. The scene confounds police: Was it foul play — or a tragic accident?

After a teen finds an embalmed head in the woods, investigators uncover a possible connection to a black-market organ trade as they try to ID the victim.

Sigrid Stevenson's chilling murder on the stage of a locked campus theater still haunts a New Jersey college as new theories about her killer emerge.

Amid eerie sightings of a tall, winged humanoid creature with red eyes, paranormal investigators explore the Mothman's seeming link to major disasters.