A follower in New Orleans built a public shrine in her honor. An actor in Albuquerque credits her with helping him land a role on the TV show "Breaking Bad." She turns up routinely along the U.S.-Mexico border at safe houses, and is sighted on dashboards of cars used to smuggle methamphetamine through the southwest desert. Popular in Mexico, and sometimes linked to the illicit drug trade, the skeleton saint known as La Santa Muerte in recent years has found a robust and diverse following north of the border: immigrant small business owners, artists, gay activists and the poor, among...