Tokyo police on Tuesday arrested a polyamorous 74-year-old man and one of his ex-wives for allegedly brainwashing an adolescent girl with a view to sexually assaulting her.

Hirohito Shibuya and his ex-wife Chiaki, 43, have been arrested on suspicion of attempting to commit constructive forcible sexual intercourse, a crime that takes advantage of a victim when they are unconscious or in no state to resist, according to investigators.

He has denied the charges, while Chiaki has maintained silence.

Shibuya was arrested Tuesday in connection with an incident that took place on Dec. 12 last year at his home in Higashiyamato, west Tokyo where he lives with his current wife and eight of his ex-wives, including Chiaki, as well as three children, investigators said.

He and Chiaki are suspected of showing the girl images of aliens over the course of several hours after Chiaki invited her to their home with the promise that she could consult a genuine fortune teller.

Shibuya then told the girl that she "would be abducted by aliens" unless she entered into a relationship with him. The girl believed him and promised to visit again, but her family and friends persuaded her to go to the police instead.

In 2006, Shibuya was convicted of trying to force another woman into joining his polyamorous family.