Sun Danyong worked for Foxconn, one of Apple's largest manufacturers. The Taiwanese firm has begun an investigation following claims made by the worker's former classmates that he had been beaten by security staff.

Apple says it is saddened by the death and is waiting for the results of the investigation. Sun Danyong was 25. He threw himself off a 12-storey building last week. He worked for Foxconn in the southern city of Shenzhen and was responsible for shipping 16 iPhone prototypes to Apple. One went missing. Sun reported the loss, and the company launched an investigation. Three days later the worker jumped to his death.

Sun's former classmates have told Chinese newspapers that during that investigation he was beaten, his house was searched and he was locked up in a room alone. They say he described the experience in an online chat with them as one of the most humiliating experiences of his life. Foxconn says it has suspended its chief of security.

The firm and the local public security bureau are investigating the allegations. Foxconn has expressed its condolences to the worker's family and set up extra counselling services for its employees. The firm is Taiwanese. It has faced allegations in the past that it treats its employees badly, claims it has always vigorously denied. The firm was also cleared at the time by Apple of any serious abuses.