Last year, it was discovered that Zhao Zuohai had spent almost 11 years in a Chinese prison for the alleged murder in Henan of a fellow villager who disappeared after a fight, but who later turned out to be alive when he revealed himself in order to obtain welfare payouts. Zhao had been forced by investigators to confess to a non-existent crime of murder, and the need for adequate safeguards for suspects subjected to interrogation by the police in criminal cases was thrown into sharp relief by his case. In quashing Zhao's conviction, Henan Higher People's Court chief judge Zhang Liyong said that judges had to learn a lesson from what had happened.
Although mainland China's 1996 Criminal Procedure Law contains strict procedures for investigators to follow when they conduct interviews, there is no right against self-incrimination, as there is in Hong Kong. A suspect is required to 'truthfully answer the questions raised', and the right to silence arises only if the question posed is 'irrelevant to the case'.
Until last year, mainland law was silent on the crucial issue of the extent to which illegally obtained evidence was admissible against a defendant at his or her trial, although that has now changed.
The Zhao case galvanised the authorities and, in July last year, the Supreme Court adopted a set of rules, in accordance with the Criminal Procedure Law and the relevant judicial interpretations, and these now regulate the admissibility of illegally obtained oral evidence in criminal cases.
The new rules are designed to prevent the use by courts of coerced confessions from suspects, or of involuntary testimony from victims or witnesses, and Article 2 stipulates that illegally obtained oral evidence 'shall be excluded and may not serve as the basis for conviction'.
In Hong Kong, the courts will not accept confessions if they have been, or may have been, obtained by force, threats, promises or by means of false representation. Former chief justice Andrew Li Kwok-nang has said the suspect enjoys 'a specific immunity whilst being interviewed by law enforcement officers from being compelled on pain of punishment to answer questions of any kind'. This is a vital safeguard, grounded in the right to silence.
That the mainland's new exclusionary rules reflect the common law principle that extra-judicial confessions are to be excluded by courts if found to be involuntary is welcome, and represents real progress towards conformity with international norms. The courts, however, need the support of others if this initiative is to succeed over the long term.
The Supreme Court has recognised that the rules require the full backing of state prosecutors, and Article 3 indicates that the prosecutors should not use illegal oral evidence 'as the basis for approving arrest or initiating prosecution'.
Once a defendant claims that a confession was obtained illegally, the court must investigate the circumstances of its making, and Article 7 requires the prosecutor, if asked, to provide 'interrogation transcripts, original audio or video recordings of the interrogation'. If necessary, the interrogators may also have to 'testify before the court' as to how the confession came into existence.
The mainland prosecutors now have a clear professional duty to avoid placing reliance upon contaminated evidence, and the investigators themselves must appreciate that if they use improper techniques to obtain evidence, this will be self-defeating, as their cases will founder, if not at the hands of the prosecutor then at those of the judge.
Although the new exclusionary rules are an important step in the right direction, they must be applied on the ground, and the danger of a disconnect between what is decreed at the national level and what actually happens in practice - in the cities, towns and provinces - is real, and must be guarded against. All too often on the mainland, legal progress in criminal cases, whether in terms of new arrangements for access to counsel, for examination of witnesses, or for provision of expenses, has counted in reality for little, and the old ways have sometimes proved very hard to change.
Deng Xiaoping said that 'we must build a modern legal system for China', and once that has been fully achieved, the new exclusionary rules will, hopefully, be seen as a major turning point in the modernisation of the mainland's criminal justice system. If so, Zhao's ordeal will not have been completely in vain.
Grenville Cross SC, is an adjunct professor at the China University of Political Science and Law, and a senator of the International Association of Prosecutors. This is an abridged version of his keynote address to an academic conference on police conduct in criminal investigations, in Hangzhou