American singer Leandra Ramm's life was turned upside down after she was featured in 2005 on Anderson Cooper's 360 programme on CNN. It was seen by Colin Mak Yew Loong, a 38-year-old Singaporean, and he harassed her for the next six years.

They had never met but he contacted her, promising to further her music career. Initially, she was grateful but when she stopped responding to him, he started sending her threatening e-mail messages and telephone calls. It continued right up to 2011 when US authorities sought the help of the Singapore police.

On Wednesday, he pleaded guilty and was convicted for criminal intimidation, harassment, criminal trespass and theft. He admitted to sending 31 threatening e-mail messages to Ms Ramm, 29.

A district court also heard that Mak went on to harass two other foreign musicians.

He had seen Ms Krasznai Tuende Ilona, 30, perform at the Ritz Carlton Millenia Hotel last year. He developed a fixation for her and after she left Singapore late last year, he would write to her. When he discovered that the Hungarian musician had a German boyfriend, Mak sent threatening messages.

Mak had also harassed Ms Veronika Sakhno, 28. He had seen the Ukrainian musician perform and wanted to date her. She turned him down politely but he took offence. On June 26, he called her names at a cafe in the Esplanade.

Mak had also sent threatening e-mail messages to businesswoman Liew Hwei Ken, 46. He claimed she had gone behind his back to engage another photographer, instead of hiring Mak to photograph a model.

Then, in April, he trespassed into the pantry of the St James Church Kindergarten and stole some biscuits. He will be sentenced on Dec 13.