It was three days after Christmas in 1992 when Steven Clark was last seen walking into a public toilet on the promenade at Saltburn-by-the-sea at 3pm.
The 23-year-old was on a family walk and had reportedly gone to use the gents' while his mother used the ladies'.
Upon coming back out, Mr Clark was nowhere to be seen and his mother assumed he had left early to return to his home in nearby Marske-by-the-Sea.
He was never seen again and nearly three decades on what happened to him has remained a mystery ever since.
Walking with a pronounced limp from a childhood road accident, Mr Clark was working with other young people with disabilities to improve their employment skills at the Rathbone Society in Redcar at the time of his disappearance.
He had also been named Apprentice of the Year.
Although nobody has ever been found in the search for answers to Mr Clarke's disappearance, detectives believe he was murdered and have been working to piece together what happened after his mother saw him walk into the public toilets.
Detectives from the Cleveland and North Yorkshire Cold Case Unit reopened the case earlier this year, finding no proof that he was still alive.
Two people have now been arrested and questioned in connection with the case, it was revealed today (Tuesday).
Cleveland Police would not disclose any details about their sex or age, but confirmed that both had been released on bail pending further investigation.
“Steven has been missing for 28 years," said Detective Chief Inspector Shaun Page from the force.
“There were many question marks over his disappearance, and as a result of our initial re-investigation and the fact that there is no proof of life, we believe that Steven has come to harm.
“I appreciate that we’re asking people to think back to the 1990s, but there may be people who knew Steven and have information that may prove vital to this case.
“I would urge them to come forward."
In Yorkshire & the Humber, there are at least 255 people missing whose cases have never been solved. Some 74 of those were children at the time of going missing.
Officers have now appealed for information from those who knew Mr Clark, or anyone who may have seen something odd on that Christmas Bank Holiday weekend.
Cleveland Police said the key to the investigation was establishing what his relationships were like with the people he knew at the time of his disappearance.
Det Chief Insp Page added: “The arrests are a significant development in the case, but we are still appealing to the public for help.
“We are continuing to conduct inquiries and searches may be carried out over the coming weeks.”
Anyone with information is asked to call 101.