He suspected two men who were getting out of the water as the three men arrived.
"There was nobody else there at the time."
With no keys or cellphones, the men were left stranded and upset. More bathers arrived soon after and they were able to arrange delivery of a spare key for their car.
The bathers described seeing an erratically-driven car as they drove to the falls from Haumoana.
The three men drove to Haumoana and surrounding districts in search of the car before filing a report with police.
"It would have been all right if they had taken out just the phones - the valuable stuff - hell, I wouldn't have cared at all," Mr Delamere said.
"But to take the whole bag and leave us there with no keys to drive out - for me that is is pretty sad."
He is appealing for the return of his eye. A replacement will cost him $1000 and until it is made he will have to wear a temporary glass piece to keep his eye socket from closing over.
"It is my glass eye I miss the most - I'm booked in for March 18 to get another one made up."
Maraetotara Falls has long been plagued by thieves and has been designated by police as an area of interest. The carpark has signs warning people of the dangers of leaving valuables unattended.
Last week Hawke's Bay Today reported two Austrian students had cash, clothing and personal items stolen from their van after its window was smashed.
Last month another group of tourists were victims of theft at the same place when their vehicles were broken into.
Anyone with information is asked to phone local police or Crimestoppers.