A Chinese civil servant who kept six women as slaves in his basement, also forced them into prostitution and to perform in pornographic videos that were posted onto the internet, according to police officials investigating the sensational and lurid case.

According to Xinhua, the official Chinese news agency, the suspect, 34-year-old Li Hao, told police investigators in Luoyang, in central Henan Province, that he dug the basement two years ago because he wanted to enter the profitable business of internet porn.

He allegedly raped the women repeatedly, the police said, and fed them only once every two days. Two of the girls who tried to fight back and escape were tortured and eventually murdered, they added. Their bodies were found in a shallow grave on September 3 during a police raid prompted by a tip from the relative of one of the sex slaves who had been able to escape.

Police freed three other women and detained Li, who is married and has one child.

The freed slaves are reportedly between the ages of 16 and 24.

However, it is not clear if some of the freed women were themselves complicit in the murder of the two other girls.

Police say the women, who were abducted by Li from nightclubs and karaoke bars, might be suffering from Stockholm Syndrome, where captives become sympathetic with their captors.

We're still investigating the case, Wang Haifeng, a spokesman for Luoyang city's public security bureau, told local media on Friday.

Nonetheless, on Saturday, Guo Congbin, director of the public security bureau of Luoyang, public apologized for his department’s failure to be aware of the presence of the secret dungeon when the slaves were kept.

He has also suspended four police officers in connection with the case.

As the police chief, I bear the responsibility, Guo was quoted as saying.

Meanwhile, the shocking nature of this case has led police and government officials to launch an investigation into the activities of other entertainment businesses, including beauty parlors, karaoke halls, saunas, and Internet cafes.

One neighbor of Li told local media: We can't imagine this. This is too cruel to believe. Neighbors are still shuddering at this.