On one occasion, they drove 15 miles to Columbia Falls on a tip, even though it seemed far-fetched. Other times they would go to check even when the description of the dog didn’t sound quite right.

“In our heart, I would always say, ‘If I didn’t follow up, what if that was her and we didn’t do anything?” Ms. King said.

Sometimes it would turn out be a different dog. On one occasion, while they were talking to a landowner at a farm, a woman came up to them and said she had just seen their dog cross the road and run into a canola field. The Kings set off running, calling for Katie.

They didn’t find her.

Day 37

Quitting Her Job

Ms. King was still working as a postal carrier back in the Spokane area. For a week in August, she had to return home while her husband continued the search.

She talked with her bosses about taking some time off. But that wasn’t feasible during summer months. Though the money had helped supplement their pensions, she gave her notice.

“Katie was just more important to me,” Ms. King said. “I just said, ‘I’ll finish this week, and that’s it.’”

When she returned to Kalispell, Mr. King had to return to Spokane. He left a note written for Katie.