Remains found in the ashes of the fire were initially believed to be human, but turned out to be the bones of a dog.
Former Waverley diner owner Tina Wolfe said she knew Mr Riley as a private man, but not as a recluse as others had described him.
"He decorated the windows at our diner every Christmas for 10 years," Ms Wolfe said.
"Far from being a recluse, he was - or still is - a valued member of our community."
Ms Wolfe said she had not seen Mr Riley since selling her business two years ago.
But a another Waverley resident, who did not wish to be named, said they had seen Mr Riley as recently as last month.
Other townsfolk variously described him as an artist and as a clean shaven, tidy and a likeable gentleman.
"He dressed more like he belonged in New York than Waverley - he often wore a long trench coat," Ms Wolfe said.
"If something has happened to him that would be terribly sad," Ms Wolfe said.
"But he may have just gone somewhere ... we are all wondering and hope that he is safe."
It is understood Mr Riley has an overdue book at the Waverley library, described as out of character.
Mr Allan said: "We wish to speak to anyone who has had contact with Kerry following November 28, 2016, when it is believed he was last seen."
Police said the scene examination was now complete, but the cause of the house fire was unknown and investigations were continuing.
Anyone with information about Mr Riley's whereabouts or which could help the investigation should contact Whanganui Police immediately on 06 3490600. Alternatively, people can contact Crimestoppers anonymously on 0800 555 111.
