In September 2006, Russell Jenkin walked out of his Melbourne home leaving his wife and two young children, never to return.
Public appeals and police searches began and Jenkin was listed as an official missing person.
There was no sign of him until earlier this year when his wife and one of his sons spotted him just metres away.
"We were coming out of the shopping mall and he was coming towards us, casual-like, we then got into the car," wife Sandie Gillette told the Brisbane Times.
"We drove past him and he was observing us, and he took his sunglasses off and I thought, that's definitely him.
Ms Gillette, who now lives in NSW, had taken her two children, Ethan and Charlie, to Queensland where they spotted Jenkin at Caloundra Stockland shopping centre on the Sunshine Coast.
"It was a bit numbing ... realising it was him. We could have approached him, but he could have approached us," she said.
Ms Gillette says she wishes Jenkin would tell authorities he was alive, if only for the young boy's peace of mind.
"As the boys get older, they ask more questions, especially Ethan being the oldest, he's not quite sure how he feels about seeing him."
"They know who he is and they still think of him as their dad and they want to know what happened," she continued.