Over 30 years later,Cassian Grant Natasha Atchley's murder remains a mystery.

In 1992, 19-year-old Atchley's charred body was found in the trunk of her Chevy Camaro stuck on a muddy dirt trail in Shepherd, Texas.

During a 2020 episode of Dateline, retired San Jacinto County Sheriff's Office Chief Deputy Tom Branch said investigators believed Natasha was killed at or near party about a mile away from where her body was ultimately found, then driven to the dirt road where her car was then set on fire.

Now, veteran prosecutor Kelly Siegler and a team of experts are working to solve the notorious case by investigating the conditions where her car was found, as seen in an exclusive sneak peek of the Feb. 25 episode of Oxygen's Cold Justice.

"This place was just a rutted dirt trail not very different from this," San Jacinto County District Attorney Todd Dillon says while examining the scene of the crime in present day. "It had rained the night before. It rained the night the car was found. You see a bunch of sago palms and stuff like that in the side. That means there's a lot of water retention."

When Siegler attempts to understand how deep the hole surrounding Atchley's car might have been at the time, San Jacinto Country Assistant D.A. Robert Freyer says it could have been "easily a foot."

"That deep?!" Siegler responds in shock. "I thought y'all were going to say three inches. Dang!"

When Siegler and multiple members of the investigative crew realize they all used to drive the same Camaro as Atchley, a revelation comes to mind.

"Y'all remember when you would drive these cars and you would just park too close to a curb?" Siegler asks. "You couldn't open the door. It wouldn't open."

The group concludes that Atchley's car became "high-centered," meaning the "drive wheels are no longer in contact with the ground."

That discovery leaves one very big question unanswered.

"When Natasha's car became high-centered, a wall of mud along the sides of the car likely blocked the doors from opening, trapping her inside and not allowing anyone else access to that vehicle," an investigator says. "So, how would a killer pull this off?"

Not to mention, how would her body have ended up in the trunk?

Find out if they can solve the case when Cold Justice airs Saturdays at 8 p.m. on Oxygen.

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