The woman said she asked her neighbors, but no one could identify the dog's owner.
Rellaford scanned the pug for a microchip and identified him as Sven, a 7-year-old pug belonging to Idaho Falls resident Michael Mitchell.
Mitchell said he was shocked to receive Rellaford's call, as Sven had been missing for two years.
"We looked around the neighborhood and posted on Facebook and different animal shelters, trying to find him. Then, at about three months, we weren't hearing anything and just didn't think we were going to see him anymore," Mitchell told the East Idaho News.
Rellaford said Sven and Mitchell seemed equally happy to be reunited.
"You could tell the dog knew where he belonged," she said.
Sven's whereabouts for the past two years remain unknown, but he was wearing a collar and had put on weight, leading Mitchell to believe someone was taking care of him.
"To get him back is a miracle. I am so grateful. I literally missed him. I always prayed and hoped that if he was somewhere, that he had a good life and was happy, but I missed him a lot," he said. "I just feel like getting your animal microchipped is very, very important, and it reunites families."