The murdered woman had a devil tattoo. But who was the devil that killed her?

This is the second in a five-part series about the oldest cold case homicide ever solved in Riverside County. The following story is based on a review of more than 1,000 pages of county court transcripts, court exhibits, police interview transcripts, archived news articles and several interviews. To explore the whole series, check out The Coldest Case, a Desert Sun true crime story.

Need to catch up? Get started with The Coldest Case, Part One.

March, 1972 – James Tilley was driving with his wife around the sparse desert streets, looking for property to buy, when he saw something that didn’t belong. A pair of bare legs stuck out from behind a short sandy berm, no more than 10 feet off the asphalt.

Tilley stopped the car for a closer look, then rushed to a friend’s house to call police.

In minutes, the Riverside County Sheriff’s Department had blocked off both ends of Cottonwood Drive, a mostly empty road between Palm Springs and Desert Hot Springs. David Dupree, a veteran detective who had been called in on his day off, searched the scene for clues.

The woman’s body was face down, slumped in the soft sand between wiry shrubs, not far from a line of tamarisk trees that swayed in a steady breeze. She wore a blue dress, dotted with red and yellow flowers, and a gold ring with a red stone on her finger. Relentless sun had dried and burned her skin, and wind had blown off strands of her long brown hair, which snagged on bushes and fluttered like streamers.

Dupree had seen plenty of bodies in the desert, so he knew what to expect. In the heat, fluids would leak out of a corpse, seep into the ground and stain the sand underneath a sickly black.

But this body was on clean, white sand.

This one has been moved, Dupree told himself. 

But it was clear the woman had been moved by scavengers, not killers. Wild animals, probably coyotes, had torn at the corpse's neck and shoulders, exposing bone, dragging the body out from behind a creosote bush that had kept it hidden from view. The woman had likely laid beneath the creosote, undiscovered, for about two weeks. 

Next to the bush, Dupree found a rock as large as a soccer ball, marked with a palm-sized blotch that appeared to be long-dried blood. Beyond that, he found a pair of women’s shoes, bright white with little rhinestones along the straps. They looked as if they had been worn once. Blood had splattered on them too.

In the newspaper the next day, the woman's death was just a blurb.

“BODY FOUND,” read a photo caption with no story. Police didn’t know who she was or how she had died.

Within a week, both of those mysteries had been solved. The woman’s skull had been crushed above her left eye, likely with the blood-stained rock found near her body. Fingerprint records identified her as Mary Elaine Costas, 22, who should have a small tattoo of a baby devil on her right thigh.

Investigators checked the body again.

The tattoo was there, barely visible through the decomposition.

So this was Costa for sure, but her identity didn’t give police much to work with.

Costa, a prostitute known as “Cha Cha,” had spent some time amid the casinos in Delano, not far from Bakersfield, and then moved to El Centro, dating farmers, before she came to Palm Springs. She was a regular downtown, where she flitted between bars and clubs, attracting lonely Johns by flipping her dress up as she danced.

Few people knew her well. Nobody had seen her recently. She had a 7-year-old son named Jimmy living with his grandmother somewhere in Crescent City, a beach town in northern California. But Costa barely kept contact with her family, so they certainly wouldn’t know who wanted her dead.

Next, police got a warrant for an apartment on North Palm Canyon Drive where Costa lived with a group of Filipino men, one of whom – maybe a boyfriend – had given her the Marine Corps ring found on her body.

The guy had women’s shoes under his bed and photos of Costa hidden beneath the paper lining of his dresser drawer, but police saw no signs of foul play. Nothing in the apartment tested positive for blood.

A week after that, Dupree sifted through rumors from the local jail, where snitches were offering up second- and third-hand tips about the murder – inmates had heard inmates tell inmates about others inmates. In one story, Costa was killed for refusing to do drugs at a party. In another, she had flirted with the wrong woman’s husband and paid the price.

But none of the snitches' stories matched the circumstances of the murder. The tips were phony. Police moved on.

Next, Dupree met with a terrified farmworker – one of Costa’s customers – who said he was haunted by the woman’s ghost. Some night before her disappearance, Costa had left clothing in his car, the man said, and now her spirit walked the halls of his farm camp each night, causing the lights to flicker.

Police ruled the farmworker out as a suspect, and Dupree kept working the case.

He contacted dozens more people who knew Costa – bar flies, pool sharks, customers and competitors – but nothing led him to a killer.  As the leads dwindled, Dupree’s calls became fewer and further apart. Eventually, the murder fell into limbo alongside so many other Riverside County cold cases.

It was technically still an open case, but there was just nothing left to do.

“I probably contacted 50 people in the first week or two,” said the detective, now retired, while testifying at a trial four decades later. “I contacted another five in the next year.”

“There were just no more leads?” a prosecutor responded.

“No,” Dupree answered. “Sometimes they come days, weeks or even years later.”

Published on July 19, 2017

PART THREE: After four years of fear, she was free. Her ex was the killer. But could she prove it?

Investigative reporter Brett Kelman can be reached at 760 778 4642 or by email at brett.kelman@desertsun.com. You can follow him on Twitter @tdsBrettKelman.