A 17-year-old student at Wah Yan College, Kowloon, was placed on probation for one year yesterday. He had threatened to kill former chief executive Donald Tsang Yam-kuen if he didn't pay a ransom of HK$100million. The teenager had also made false bomb threats. Ho Lok-hei is a Form Five student with Asperger's syndrome. The disorder can cause sufferers to have difficulties with social skills. Acting Principal Magistrate Amanda Woodcock told Kwun Tong Court she had taken into consideration in sentencing that the student was unable to handle the pressures of exams. She said these factors lessened the seriousness of his offences. Ho will have to observe court rules about where he can work, study and live. He must take part in group activities and receive psychiatric treatment.