Chinese authorities on Tuesday put to death a man who held six sex slaves in his basement and murdered two, state media reported.Li Hao, a 36-year-old former clerk, was executed after being convicted of "murder, rape, illegal detention, organised prostitution and manufacturing pornography for profit", the state news agency Xinhua said.In 2009 Li dug a "dungeon" in his basement and confined six women there for periods ranging from two to 21 months, where he "repeatedly raped" them, it added.Five were prostitutes whom he tricked into his prison by soliciting their services, and one was selling birth control products, the People's Daily website said, adding that Li installed seven metal doors to prevent their escape.The victims ranged from about 16 to 23 in age, and one who was 20 at the time of kidnap became pregnant, it said.Li also forced three of the women to kill two of the others, Xinhua said. One who participated in both murders was sentenced to three years' prison while the rest were put on probation.In 2011 Li had his surviving captives make obscene videos online and have sex with customers.He spent two weeks a month with the women while telling his wife he worked nights as a guard, the Southern Metropolis Daily reported in 2011.Li was caught in September that year after one captive escaped and went to the police.The case recalled the actions of Austrian Josef Fritzl, who held his daughter Elisabeth as a sex slave in a cramped windowless dungeon for 24 years and fathered seven children with her. He was jailed for life on rape and murder charges in March 2009.

Also in Austria, Natascha Kampusch was kidnapped at the age of 10 and held captive in a tiny cellar for eight and a half years until she escaped in August 2006.More recently former US bus driver Ariel Castro hanged himself in his cell in September after being jailed for life for kidnapping and raping three young women he held as sex slaves for a decade.