Chinese authorities have arrested a former civil servant of the Technological Supervision Bureau on charges of kidnapping six women and confining them in an old basement, where they were forced to become his sex slaves for two years.

Two of the captives were murdered and buried in one of the basement rooms that Li Hao reconstructed four years ago, police said. He used the murders to instill fear among four remaining women, who worked at nightclubs and karaoke bars before being kidnapped.

China Daily reported that one of the captives escaped and went to the authorities to get help. Police raided the basement, arrested Li and rescued three more women. He has been detained for investigation and tests to determine his mental state.

Investigators said some of the women developed a "Stockholm syndrome" as they proudly told the police of their sexual encounters with Li.

The woman who escaped told the authorities each of them had been raped for the past two years. Sometimes, when Li needed money, he would go out with one of the girls, try to hook her up with another man and pocket the money. It was during such an incident when the woman escaped.

The women were deliberately kept weak, fed little to ensure they could not fight back. Three of them were released Friday while the fourth has been detained for possibly helping Li in killing the other two.

Li's wife has denied knowledge of her husband's crimes and said she was made to believe her husband works as a gatekeeper at night.