''I believe that the strong suspect is alive and in New Zealand, as things progress, we'll continue to work away on that,'' he said.
''Entreaties to the Crown haven't bore any fruit around charging an individual. But I never give up hope on that, because that individual is still around, there's potential still for Tim's remains to be found.''
The file was reviewed as recently as December, and the four cardboard boxes containing the case files were sitting in Croudis' office.
Police believed Trotters Gorge was a strong area of interest in the search for Pridding.
''Police in the past have spent quite a bit of time in the area of Trotters Gorge, looking there, and based on what I know, both from the suspect and the inquiry file, that's a potential area of interest.
''We put staff in Trotters Gorge, we put a helicopter up, we did a number of things of that nature, but it's such a vast area, without an indication of where that may be, it makes it tough.''
Pridding was believed to have been involved in minor drug dealing before his disappearance, the Otago Daily Times reports.
Police still believed that was the strongest motive behind his death.
''He did dabble in the drugs area, and I know that's distressing, and was distressing to George and Betty [Mr Pridding's parents], but he was involved in moving mainly cannabis-based drugs.
''Drug sales and debt were looked at as a very strong basis for motive.''
But police were at a disadvantage with the investigation from the start.
''Because of the transient lifestyle that Tim led, we didn't really know about it for a month that he was gone.
''That really put us at a disadvantage because of people's memories, that made things difficult.''
Despite the decades that have passed, Croudis still believes the case would be solved.
''I'm confident there are still people out there who have spoken to the people that knew, or hung around with Tim at that time, that could assist us, but for one reason or another, they choose not to.''
• Anyone with information should contact Dunedin police.