Chao Xu, 33, may be one of worst sex offenders in British criminal history, police fear Chao Xu, 33, may be one of worst sex offenders in British criminal history, police fear A businessman has been jailed for life for drugging women then subjecting them to sexual attacks which he recorded for his pleasure, as well as committing hundreds of other sexual offences. The Metropolitan police fear Chao Xu, 33, may be one of the worst sex offenders in British criminal history. The judge said his