LAS VEGAS (KTNV) — A 17-year mystery begins with a single haunting question: What happened to Steven Koecher?
The Utah native was just 30 years old when he vanished from the Sun City Anthem community in Henderson. His car was found abandoned in a cul-de-sac on Dec. 14, 2009.
WATCH: New true crime docuseries shines light on Henderson cold case
With no signs of foul play, his family found out he was missing when police called about a parking violation.
"It had been there for four days, and they were calling to tell us to come pick it up. We don't want to tow it. We want to save you a tow charge. It was just a parking enforcement thing," Steven's father, Rolf Koecher, told Channel 13 in 2009. "We have no idea why he was here. He never indicated to us that he was coming to Nevada."
To this day, no one knows why Steven traveled from St. George to Henderson.
Now, Steven's case is getting national attention in the new true-crime series "Somebody Knows Something." Investigators are hoping to unearth new leads.
We spoke with the show's host, Kara Chamberlain, a violent crime survivor and former law enforcement officer, about the critical first hours of the investigation.
"With Steven's disappearance, he is an adult man. He goes missing in the Las Vegas area. Las Vegas is an area where a lot of people go missing every single day," she said. "So, obviously, law enforcement is going to be approaching him being missing with that knowledge, as well as the fact that he is an adult man. So there's not going to be the same level of urgency placed on looking for him as a missing person."
CHANNEL 13 ARCHIVES: 2010: Search is on for man who disappeared in Henderson
Early on, the case stalled. The only real evidence: a fleeting glimpse of Steven on surveillance video, walking away from his car and into the unknown. His desperate family spent months scouring the valley, chasing down every tip and potential lead.
"We've had several sightings or unconfirmed ones and very vague ones that he was on some buses in certain parts of town," Rolf told us in 2010. "It's really difficult. There's times where we actually get frozen, you know, because we can't do anything as we get so down about this."
In 2015, a new tip sparked a massive search. Red Rock Search and Rescue teams combed 25 miles of rugged desert.
"So we decided to go high up in the mountains in this area and work down through the washes," a volunteer told us at the time. "So that was kind of a, in previous searches, we were working in a certain area, like a specific area that was close to where he was last seen."
However, the desert kept its secrets. They found nothing.
CHANNEL 13 ARCHIVES: 2015: Red Rock Search and Rescue looks for clues in missing person case
Over the years, theories from private investigators have swirled — questions about his faith, his sexuality, even a dispute over unpaid rent to a landlord with a criminal record. But with only circumstantial clues, the truth remains just out of reach.
"There's a lot of mystery. There's a lot of things that are circumstantial that we can say oh, well, A plus B usually equals C," Chamberlain said. "So maybe we can make some assumptions, but we have not been able to find anything that's conclusive about why Steven was in the Las Vegas area."
Now, the hope is this new exposure will compel someone to come forward. For Steven's family, it's about finding one thing: closure.
"Having no closure and no idea what has happened, it's something that you can't really move past," his brother, Dallin, told us in 2015. "It makes it hard for you to really let go of it."
"Share Steven's picture. Share the episode. Share the case because the chances of somebody out there knowing something, even if it's not you, it might be someone you know or someone who knows someone that you know," Chamberlain said. "So just keeping Steven's story out there, keeping it alive, sharing it, that's the biggest hope and the biggest thing that I ask anyone watching to do."
"Somebody Knows Something" is now streaming on Hulu and Disney+.
If you have any information related to this case, please contact local law enforcement.
WATCH TRAILER: Somebody Knows Something