Plot Synopsis

Each hour-long episode of MARK OF A KILLER follows the story of an investigation guided by the killer's postmortem signature and features first-hand accounts from detectives who worked on the cases, interviews with criminal psychology experts and with family members and friends of the victims. Some killers are collectors who obtain perverse gratification by habitually stealing mementos from murder scenes, from jewelry to shoes, keys to even body parts. These clues are left to taunt law enforcement and investigators while simultaneously building up their notoriety. Whether it's text scrawled onto the victim's body, a cryptic note or a way of positioning the deceased, what is left behind is a trademark clue that ultimately aids the investigation in stopping these murders and bringing the killer to justice. The series opener, "Posed to Kill," of this true-crime documentary dives into the infamous Gainesville Ripper who helped ring in a new school year at the University of Florida in 1990 with a string of murders, posing his victims in grotesque ways and cutting their clothes from their bodies. These trademarks are at the center of each tale, and prove to be crucial factors in identifying the killers and ending their reign of terror.

The sophomore season of MARK OF A KILLER premiered on Thursday, April 9, 2020 at 9pm ET/PT on Oxygen -- the same day the cable network kicked off its "12 Dark Days of Serial Killers" programming event. The season opener, "Killer Caller," follows Twin Cities, Minnesota, police as they hunt down a killer who confesses over the phone to a string of murders in a chilling, high-pitched voice, begging for forgiveness. No one can identify him until one woman survives a brutal attack.
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Season 3 debuted on Monday, April 12, 2021 at 8pm ET/PT on Oxygen with a new title -- MARK OF A SERIAL KILLER -- during the cable network's "Serial Killer Week" event. In the season opener, "The I-40 Killer," a killer is murdering and mutilating young women along the Route 40 corridor in Delaware. But when investigators set up an undercover operation, the hunter soon becomes the hunted. New episodes also debut on Tuesday and Wednesday of "Serial Killer Week."