Conor and Shiela Dwyer, who lived at Chapel Hill, Fermoy, Co Cork, have been missing since April 1991, according to a missing persons notice from An Garda Síochána.
The Dwyers, both aged in their 60s, were last seen walking to St. Patrick's Church in Fermoy on April 30, 1991.
After being notified some days later that the couple was missing, Gardai went to the Dwyer home and found the house secure and all personal items such as clothes, passports, and money still in the house. Their bank accounts have also not been accessed since their disappearance.
However, their car, a white Toyota Cressida registration number 5797 ZT, was not at the house and has not been located to date.
No trace of the couple has ever been discovered despite several Garda appeals and numerous reported sightings in Ireland, Germany, and France.
The alleged sighting in Germany took place in Munich in 1993 and intrigued gardaí as Conor Dwyer had spent time working for German businessman Fritz Wolf, who owned a house near Fermoy. However, local police and Interpol investigated the sighting and dismissed it as a well-intentioned but mistaken report.
Joe Watkins, a retired Garda sergeant who investigated the disappearance, told the Irish Independent that the case was "baffling."
"Everything was there. All of their property, their money, their passports, and all of their possessions," Watkins told the Irish Independent in a recent interview.
"I always believed that the Toyota Cressida was the key – if we could have found the car, the car was the link."
Watkins added that every member of An Garda Síochána involved in the investigation was desperate to find answers to bring some closure to the family.
The fact that a couple went missing rather than an individual made the disappearance all the more baffling for law enforcement.