Riku Sendo (not his real name) is a self-confessed groping addict.

"Molesting is an addiction," the 37-year-old tells Spa! "My only choice is to spend the rest of my life as a criminal."

Sendo always had an interest in the national affliction of chikan -- the name the Japanese give to those who feel up female commuters on the country's jam-packed trains.

But Sendo confined his interest to watching videos dedicated to the genre up until four years ago. It seems the molestation movies made for blokes like him were just a tad too authentic.

"After watching them for a while, I realized I could probably get into the act for myself," he says.

At 33, he started riding trains just so he could fondle women's buttocks. It led to his arrest, and when his employer at the time learned of his fate, dismissal.

"I first realized there was something wrong with me when I started going to sex businesses. I couldn't get a hard-on at a regular brothel, it had to be a club where the workers pretended to be commuters being molested by a chikan," the groper tells Spa! "I was totally impotent in every situation except when I was pretending to be a chikan, when I'd get as hard as a rock. It was heart-breaking."

Following his first arrest, Sendo held off from molesting anyone for two years. But the sex joint he frequented to fulfill his fantasies was caught up in a wave of police raids that swept through Tokyo, depriving him of a place to relieve his sexual frustrations. He found himself riding trains on the prowl once again, only this time he took a full-frontal approach to his victims, brazenly grabbing between their legs instead of trying to get them turn the other cheek, as it were.

"It was all because I read an online forum about a guy who'd kept on groping even after he'd been arrested. I couldn't find myself a wife and I was pretty down about my prospects for life," he says. "I'd get up early in the morning and ride the trains around before going off to work. I'd aim for the most crowded areas and just grope. I ended up getting arrested for indecent assault. I'm actually still on probation now."

Sendo says he's well aware that groping is a crime. But he says his urge to molest is an illness over which he has absolutely no control.

"It's not like you can go to a doctor and say, 'Hey, I can't get it up unless I'm groping someone,'" he says to Spa! "My family have disowned me and I can't see any way to cure me of this disease, so I've recently started coming to the conclusion that I can handle being a criminal molester for the rest of my life." (By Ryann Connell)