How did Leo Sharp—a day-lily farmer, World War II veteran, and great-grandfather—become a drug mule for Mexico’s most powerful drug cartel?

Sharp’s lawyer, Darryl A. Goldberg, said that it was unclear precisely when Sharp began working with the cartel, but he believed it started at the day-lily farm. “He has Mexican fellas working on the farms,” Goldberg said. “They happen to know people who introduced him to other people who asked him if he wanted to get involved in something.” His first assignments were to ferry cash, he said. “And then it morphed into something bigger.”

Law-enforcement authorities said the cartel deliberately recruited couriers who played against type. Walter Ogden, a 57-year-old man from Oklahoma, was another trusted driver. Ogden has been on disability since 2010 and has had four heart attacks, according to his lawyer. He was a former heavy-equipment operator for an excavation company in Oklahoma City and, like Sharp, had no criminal record.