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Is it a photograph of a previously unknown victim of Houston serial killers? Or just another "red herring" in a criminal case that dates back 40 years?

Nobody really knows. The photo itself is a blurry Polaroid depicting a toolkit next to a young boy. His expression? Hard to read. Could be smiling. Could be terrified.

But it's where the picture was found that is most ominous.

It was discovered by filmmaker Josh Vargas, who is directing a docudrama about Elmer Wayne Henley.

In the early 70s, Wayne Henley and his pal, David Brooks, procured victims for a sexual sadist named Dean Corll.

Their victims – all teenage boys – were handcuffed on a torture board and terrorized with implements from Corll's toolbox.

They were raped and murdered, while a radio played loudly to mask the screams.

On Vargas' set, the torture board and the radio are props.

But the shirt on the back of the actor portraying Elmer Wayne Henley is not.

"That's the shirt Wayne was arrested in," said Vargas. "It's what he wore when he shot Dean."

Henley's murder of Dean Corll in 1973 ended it all. But not before as many as 30 teenage boys – perhaps more – were snuffed out. Many of them, lured from their homes in Houston's Heights area.

Josh Vargas wanted his script to ring true. So he interviewed Wayne Henley in prison and Henley's mother at her home.

"She told me that she'd kept everything that he'd had prior to his arrest and boxed it all up and hoarded it in a school bus," Vargas explained.

In that school bus, parked in a field, the filmmaker found Henley's personal effects. And many of those actual items appear in his film.

Chris Binum plays Henley in the movie. In one scene, he wears a tank top that belonged to Henley. On the back of the shirt is a quarter-sized spot that appears to be long-dried blood.

"You can see the bloodstain right there," said Binum. "So who knows what happened in this shirt? I know this is one of the shirts that Wayne used, while he was killing other victims."

In the boxes of Henley's belongings, Vargas also dug out a Polaroid camera and an instant photo that was apparently snapped with it.

"Kinda started looking at it," recalled the director. "And then right off the bat I noticed the toolbox. Then I noticed what's in the toolbox. Then I noticed the kid's face."

Was it the final snapshot of a previously unknown victim? Josh Vargas says yes, undoubtedly so.

"He's dead," said Vargas. "He's dead, there's no question about it. That was their rule. If they were handcuffed, they were dead. There's no other way around it."

But Harris County authorities are not so sure. They are, however, hoping for more information from the public on the child in the photo.

"If there is anything that is meaningful regarding this boy, we'd really like to hear about it," said Dr. Sharon Derrick, a forensic anthropologist with the Harris County Institute of Forensic Sciences.

Derrick has made it her mission to put a name with the remains of the last few unidentified victims. She says there remains only one body that has not been properly identified.

"It was a very tragic occurrence," said Dr. Derrick. "And it continues to haunt the families, continues to haunt our office."

As for Josh Vargas, he wanted to tell Wayne Henley's story. What he didn't count on was being swept up in that story.

The photograph he uncovered may be among the most haunting images associated with the Houston mass murders. Or it may be completely irrelevant.

Either way, Vargas wants to know why it waited to be discovered by a film director – and not by the police, back in the 70's.

"I cannot fathom how you can arrest someone for one of the worst mass murders in American history," exclaimed Vargas, "and not search his bedroom.

Vargas' film will be called "In A Madman's World." Shooting wrapped on Sunday.

Meantime, the real Elmer Wayne Henley is up for parole. Would Vargas vote to release his film's protagonist?

"No, I don't think he should get out. He killed people."

Read more at myfoxhouston.com

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