Risa Yamada grew up fatherless and struggled to find consistent work until she stumbled on an intriguing job listing — one of a growing number of advertisements posted on social media by Japanese criminal gangs.

Hired to impersonate a police officer, she thrived, wheedling significant sums of money out of Japan's many lonely, wealthy and naive elderly people on the phone.

"I didn't think I could ever work a normal job," the 27-year-old told a Tokyo court in July before being sentenced to three years in jail.