A playing card left at a murder scene connects a string of killings in this docuseries tracking a notorious serial killer who terrorized Spain in 2003.A playing card left at a murder scene connects a string of killings in this docuseries tracking a notorious serial killer who terrorized Spain in 2003.A playing card left at a murder scene connects a string of killings in this docuseries tracking a notorious serial killer who terrorized Spain in 2003.