The fever did subside and the girl, who was referred to as X in court, started to believe that Yuen had magical powers.

Yuen, who had been dating the victim's sister for three years at that stage, then convinced her that the sexual 'ritual' had to be continued or she would get cancer before she turned 30.

X told the District Court how Yuen initially had sex with her every day beginning in 2004. The rituals then continued on a weekly basis until early last year, when X grew suspicious after Yuen insisted he needed more time to cure her.

When Yuen tried to end the 'rituals', X said he threatened to break up with her sister and said this might lead to the older girl's death as she was fragile and could commit suicide.

He also said that without his presence the sisters' mother would be killed by 'little ghosts' raised from the dead by her ex-boyfriend.

The defence argued that it was X, who admitted losing her virginity at the age of 13, who took the initiative to tempt Yuen.

Yuen claimed the two had a good relationship until Yuen chose the older sister over her, prompting X to report him to the police.

The arguments were dismissed as lies by the court yesterday.

Judge Frankie Yiu Fun-che said Yuen exploited X's fears for her family's well-being.

After the girl alerted police, Yuen sent her a text message saying: 'Do you want to bring doom upon me after all these years in a relationship?

'Things can be changed before the police hand over evidence to the Department of Justice. If that is done I'm doomed. Can you reconsider carefully?'

The judge said that message demonstrated that Yuen was aware he had broken the law.

Yuen was convicted of seven counts of procuring another person for unlawful sexual acts by false pretences between September 2004 and January 2010.

The case was adjourned until October 20 for the preparation of a report on the impact of his crimes on X., who is now a university student. Sentencing will follow.

Yuen was remanded in custody.