Zhao Zuohai said on Tuesday he was tortured to confess the murder, saying that police beat him with a long stick, set off fireworks over his head, handcuffed him on a stool and would not let him sleep for about a month.

"They taught me how to plead guilty. They told me to repeat what they said, and I had to, or I would be beaten", Zhao said. "They wrote down what I repeated and said it was my confession."

Zhao said he did not appeal because he was afraid of getting beaten.

"In jail, others treated me better because I'm an old man. At least nobody beat me there."

Zhao's case has triggered heated discussion among legal analysts on preventing torture in interrogation and the necessity of improving supervision in the legal system.

"Although the case occurred 10 years ago, it is a reminder of the legal environment and its mechanism", said Zhao Binzhi, director of the law school of Beijing Normal University. "Torture in interrogation still exists today. It is not rare."

Fan Chongyi, a law professor from the China University of Political Science and Law, said videos and recordings should be made and suspects' lawyers should be present during interrogation. Courts should also refuse evidence gained through violent and illegal means.

"We hope some amendment will be made to the Criminal Procedural Law to establish a functional system to prevent the use of torture in interrogation."