One rainy afternoon in August, Jean Booth scurried up the stairs of a nondescript Thai restaurant, shook out her blue, shoulder-length hair and took out her phone. She bit her lip; no messages.

Her boyfriend, Donnie, was due to arrive at the airport in a matter of hours, but Jean hadn’t heard from him all day. Over the next half-hour, Jean checked her phone a few more times, but Donnie didn’t text or call. Part of her knew he wouldn’t — they had never met in person or even spoken on the phone.