The county clerk immediately knew something strange was going on last fall. A mail ballot had arrived from Suzanne Morphew — a woman missing since May. “There’s posters all over our town,” said Lori Mitchell, the clerk and recorder in Chaffee County, a Colorado community of about 20,000 rocked by Morphew’s disappearance last Mother’s Day. “Constant things in the news about her. There’s people at the grocery store passing out fliers.” The ballot didn’t have Morphew’s signature as required, Mitchell said. But someone had signed on the “witness” line: The woman’s husband, Barry Morphew. “I was stunned,” Mitchell recalled. “I...