Listen up, true crime fans!

Things are about to get dark on Oxygen as the network has announced its "deadliest event," 12 Dark Days of Serial Killers, airing April 9 through 20. Through two new specials, Catching a Serial Killer: Sam Little and Snapped: Notorious Hollywood Ripper, and the season premiere for Mark of a Killer and the season finale for The DNA of Murder With Paul Holes, Oxygen is producing the biggest event in true crime history.

But wait, there's more…

Since the exclusive teaser above promises true crime content "all day, all night," the network's other prominent episodes—including Serial Killer with Piers Morgan, Dateline: Secrets Uncovered, Smiley Face Killers: The Hunt for Justice, It Takes a Killer and more—will also air during the event.

"The darkest names, the darkest premieres," the just released footage above notes. "Witness the biggest event in true crime history."

So, for a taste of what's to come for 12 Days of Serial Killers, take a look at the new descriptions below.

Mark of a Killer season 2 premiere: Thursday, Apr. 9 at 9 p.m.

"Some killers are collectors who obtain perverse gratification by habitually stealing mementos from murder scenes, from jewelry to shoes, keys to even body parts. Others leave their mark at the crime scene, signatures of their personality that create insights into their profile," Oxygen states in a press release. "The premiere episode 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."

The DNA of Murder With Paul Holes season 1 finale: Saturday, Apr. 11 at 7 p.m.

"The series follows Holes as he dives into unsolved homicides by analyzing the physical and emotional DNA left behind during the violent interactions," the network adds. "In the season finale airing on Apr. 11, Kathleen Heisey, an elementary school principal, is discovered dead inside her home. Paul Holes investigates this shockingly provocative and brutal scene that sent shock-waves through Bakersfield, California in 1998."

Catching a Serial Killer: Sam Little premiere: Sunday, Apr. 12 at 7 p.m.

"In May of 2018, FBI and local law agencies were stunned when 78-year-old Sam Little confessed to murdering over 90 women across 17 different states on a killing spree lasting 35 years. Thus far, over fifty of his victims have been confirmed by the FBI, making him America's most prolific serial killer. What fueled his deadly rampage? How did he get away with killing so many, for so long?" Oxygen details. "In this compelling two-hour special, former prosecutor/investigative journalist Beth Karas follows Sam Little's trail of terror in hopes of finding out how this calculated killer evaded capture and stymied investigators at every turn."

Michael Gargiulo

Santa Monica Police Dept.

Snapped: Notorious Hollywood Ripper premiere: Sunday, Apr. 19 at 7 p.m.

"The long running hit series, Snapped, takes a look at one of the most sensational serial killer cases in recent history in a special 90-minute episode. From 1993 to 2008, Michael Gargiulo stalked, befriended and murdered three young women and attempted to kill a fourth," the network states. "The episode will reveal how a stone-cold murderer living under the radar in L.A. came to be known as 'The Hollywood Ripper,' and proving that all that glitters is not gold."

So, if you're interested in learning more about Ted Bundy, Jeffrey Dahmer, Ed Kemper and other notable serial killers, be sure to tune in to Oxygen this April.

Oxygen's 12 Dark Days of Serial Killers kicks off Thursday, Apr. 9 and runs through Monday, Apr. 20.

(E! and Oxygen are both part of the NBCUniversal family.)

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