Editor's note: This story contains graphic details.
Before Rex Heuermann's arrest, years of unanswered questions about the murders of at least 10 sex workers birthed the phantom personas of "LISK" and the "Manorville Butcher."
Four of the victims – known as the "Gilgo Beach 4" – have been connected to Heuermann, who is believed to be "LISK," short for Long Island Serial Killer. He was charged in three of the killings, and is the prime suspect in a fourth.
But there are at least six more victims – including some who were dismembered – that were found in the same vicinity along the South Shore of Long Island by April 2011, which pushes a fiercely debated question back to the forefront.
"This is hard to talk about, but is this same killer or are there two?" said Josh Zeman, a filmmaker and producer who sunk his teeth into this case for a 2017 documentary called "The Killing Season." "It's been really baffling to some of the best minds in the country."
Further complicating the notorious New York cold case is when and where the body parts of the dismembered victims were found.
The skull of one victim – known only as "Fire Island Jane Doe" – was found on Gilgo Beach in 2011, but her legs were found about 16 miles east on Fire Island in 1996.
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Valerie Mack's head, hands and right foot were found on Gilgo Beach in 2011, but her torso was found 11 years earlier in Manorville, New York, which is about 40 miles east of Gilgo Beach.
Similarly, Jessica Taylor's skull, hands and one of her forearms were found around the beach along Ocean Parkway in March 2011, but her torso was found in Manorville in 2003.
Law enforcement also found body parts of a young Black or biracial Jane Doe, known as "Peaches" after a distinguishing tattoo on her left breast, near Gilgo Beach in 2011. But her torso was found in Hempstead Lake State Park in 1997.
A toddler that investigators said was a child of "Peaches" was also found on Gilgo Beach in 2011.
"So you have a killer who's leaving torsos in Manorville, additional body parts in Gilgo Beach and the same person, theoretically, has left other body parts in other parts of Long Island," Zeman said in an interview with Fox News Digital.
"It's wicked confusing… The fact that these body parts, these torsos, were found in Manorville is why people call this killer, ‘The Manorville Butcher.’"
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Enter John Bittrolff, a Manorville resident and carpenter by trade who was arrested through DNA in July 2014 for killing two sex workers named Rita Tangredi and Colleen McNamee.
Theories concocted by the public and law enforcement immediately tied Bittrolff to the Gilgo Beach case, but he beat his victims to death and left them on the side of the road, a third different MO.
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"Many said he must be the Gilgo Beach Killer. He must be the Manorville Butcher. He must be responsible for all these bodies along Ocean Parkway," Zeman said. "But right now, we don't know.
"It was originally said during his trial, that an [assistant district attorney] said he might be connected to more bodies, but we've yet to find out if that's really true or speculation."
Bittrolff was convicted in 2017 and sentenced to 50 years to life in prison.
"He remains somewhat of a tangential and mysterious figure in this whole question if there's one or multiple killers," Zeman said.
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John Bittrolff was one of Heuermann's 200-plus alleged Google searches related to the Gilgo Beach case, according to his bail application, which detailed thousands of Google searches for explicit pornography and nearby sex workers.
Fox News Digital is not describing many of the Google searches due to their explicit nature, but "John Bitroff (sic)" was listed as No. 14 in searches (pictured below).
There was one alleged Google search that caught Zeman's eye: "Asian twink tie up porn."
Twink is defined as a gay or bisexual young man with a "slim, boyish appearance," according to dictionary.com.
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"Personally, I always thought it was two killers," Zeman said. "But one of the bodies that was found along Ocean Parkway was an Asian male, so that suddenly made me think that suddenly we are dealing with one killer."
The victim he's referring to still hasn't identified. He's described as a young, biological male found wearing women’s clothing.
Law enforcement believe the victim was dead for about five years when he was found in April 2011. All that's left is a composite sketch.
"I still don't know (how many killers), and this was a big problem for Suffolk County from the beginning," Zeman said. "It's been said (former Police Commissioner) Richard Dormer was fired because he got in an argument with the DA whether it was one serial killer or two.
"So this debate about one serial killer or two has been raging since the very earliest days of this investigation."
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Retired Reno, Nevada, Police Lt. Joey Walker, who created the "Serial Defense" program that includes a podcast and life-saving techniques to fend off sex assaults and serial killers, broke down the case for Fox News Digital.
He started the interview by saying, there's an old adage, "No sense makes sense," which is particularly true in this criminal case.
He drew a diagram similar to a clock with each number as another possibility. At the center is the "dump site," which in this instance is Gilgo Beach.
With serial offenders of any crime, they likely will repeat what they know works, Walker said, so if one person committed all the murders and dumped evidence (or in this case bodies/body parts) without being caught, the "area is safe" and could be used again.
Then there's the possibility a single offender committed some or most of the murders, and by coincidence another killer used the same dumping ground, Walker said.
He used the cases of Ted Bundy and Edmond Kemper to illustrate why serial killers might scatter body parts.
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"Finding human remains from one homicide victim in different locations could have a ritualistic component, where the killer utilizes that body part as a souvenir, or for their sexual gratification," Walker said.
Because body parts were found several miles apart, it was likely done on purpose either to confuse investigators or to thwart identification, which is what Whitey Bugler did.
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And serial offenders study, read and watch other offenders, and "perhaps mimic their methodology, whole or in part, of their successes," he said.
To Walker's point, Dennis Rader, known as the serial killer "BTK," wrote in a letter to Fox News Digital that he sees Heuermann as "a clone of me."
Bodies or evidence can be discarded "purposely or haphazardly," and that often depends on the sophistication of the offender, Walker said.
"If the offender discards items in several locations, it may be a purposeful attempt to cast off suspicion from themselves where it might be connected and attributed directly to them," he said.
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"I was arrested age 59. Married, two kids," Rader wrote in the letter. "Husband, dad longtime a serial killer, stalker, used electronic devices, lives in a neighborhood undetected."
With all that said, it will likely "take years, if ever, before the totality of the crimes committed are attributed to one or more persons and ultimately resolved," Walker said.
As it stands now, Heuermann is accused of killing Melissa Barthelemy, 24, Megan Waterman, 22, and Amber Lynn Costello, 27, and is the prime suspect in Maureen Brainard-Barnes' murder.
He was charged with six counts of murder (first- and second-degree for each victim), and pleaded not guilty to all charges.
Prosecutors haven't said if they believe Heuermann is involved with any of the other six victims on Gilgo Beach.
But his arrest sparked law enforcement agencies across the country, including South Carolina, Las Vegas and Atlantic City, to reexamine missing persons cases and cold cases to determine if Heuermann is involved.
