The family of 22-year-old Sudipto Gupta, student activist who died in police custody after he was arrested during a students' protest on Tuesday, has demanded a CBI probe into his death. An autopsy report released yesterday said that Mr Gupta had a broken jaw and fractures on his head, as well as injury marks all over his body. Chief Minister Mamata Banerjee has said that his death was an accident, but Mr Gupta's family says they want to know how did such grievous injury marks appear on his body if it was an accident.