Twenty-one years after a Northeastern State University student vanished along with his pickup truck, investigators and family members say they are no closer to understanding what happened on Dec. 13, 2004, a day marked by a final phone call, a troubling sighting and a trail that went cold within minutes.

Stephan M. Adams, 26, of Webbers Falls, had finished an exam in Tahlequah late that morning and phoned his girlfriend around 11 a.m., telling her the test had gone well and that he planned to give a man a ride to Keys. Authorities later determined he was already south of Tahlequah at the time of that call. Adams never returned to the apartment he shared with his cousin, leaving behind inhalers, money and other belongings he usually carried.

Around 11:30 a.m., his cousin attempted to reach him — the call rang once, then went to voicemail. Every call afterward went straight to voicemail.

In that same halfhour, Adams was seen at a convenience store in Cookson, where witnesses reported he appeared upset and agitated. He bought a soda, lingered outside briefly and then drove away alone in his white 1995 GMC pickup with Oklahoma license plate SCQ-714. Neither he nor the truck has been seen since.

“I remember that day like it was yesterday,” Carl Adams, Stephan’s father said. “It was unseasonably warm, kind of like it is now.”

Adams had been expected in Webbers Falls later that day to visit his mother but never arrived.

Carl said his son’s disappearance came just days before a scheduled court hearing connected to a contentious custody dispute with his ex-wife over their daughter.

He said investigators have long considered the possibility of foul play but have not named any suspects, citing a lack of definitive evidence.

“Stephan was a good kid, he was loved by everyone who knew him,” Carl said.

Family members have voiced their own theories over the years, including concerns about individuals connected to the custody case, but authorities have never substantiated those claims. A reported sighting of Adams at the Cookson store has also been the subject of internal debate within the family, with some questioning the reliability of the witness.

Another lingering mystery is the unidentified man seen outside a Dollar General near Adams’s apartment the morning he disappeared. The man reportedly arrived before 8 a.m. and stayed for several hours, telling bystanders he was waiting for someone. Investigators do not consider him a suspect but believe he may have information relevant to the case. He has never been identified.

“They later found two individuals who had sold Stephan’s textbooks back to the college and stole all his stuff,” Carl said. “But nothing ever came of it.”

Despite obstacles with law enforcement and other entities, Carl said he appreciates District Attorney Jack Thorp and so many others that have “been so good to him” and his family, including the media.

“I will be 70 next month and my health is not the best,” he continued. “I know in my heart that Stephan is dead, but I hope someone out there will read this story, be a decent human being and come forward with the information we need to fully prosecute the people who did this. We just want to keep his story and memory alive; we don’t want him to ever be forgotten, and that’s the hardest part.”

Other theories have focused on the rural roads between Tahlequah and Webbers Falls, where dense woods and deep ravines could conceal a vehicle for decades. Some investigators have acknowledged the possibility that Adams could have crashed, gone off the road and remained undiscovered despite repeated searches.

“I couldn’t tell you how many times we searched Lake Tenkiller, creeks and waterways,” Carl said. “We hoped to find his truck or any evidence, but still haven’t. Of course, that doesn’t mean that we are going to stop looking, but I think the truck was hauled off and chopped with the intentiom of it never being found.”

Carl said he has had no contact with his son’s daughter since his disappearance, but hopes one day, now that she’s an adult, that she will reach out to him.

“I think she’s in college now,” he said. “And if she wanted to know more about her dad or who he was, I would welcome her with open arms.”

With no physical evidence, no vehicle and no confirmed sightings, the case remains one of Oklahoma’s most perplexing missing-persons investigations.

Anyone with information is asked to contact the Oklahoma State Bureau of Investigation at cold.case@osbi. ok.gov.