Inmates, both heterosexual and gay, pay $19 to post their photograph and a short note on the site. Women inmates are also invited to join hotprisonpals, but none has applied so far.

"We don't require that prisoners say what crime they committed," said Rupp, a 30-year-old photographer who runs the site from his home in the Thai capital, Bangkok.

"We take everybody. If they are murderers or rapists they are not going to put that in the ad..."

"It's a thrill for women. These are good looking guys and they can seem really exotic from the outside," said Rupp. "It's a fantasy. You don't see any of their flaws."