In criminal procedure, it is allowed to use some kinds of investigation strategies, such setting up a policet rap, sending undercover policemen to organized criminal group and deception in interrogation, which obvious contain an element of deception. In order to uphold the image of the state, social credibility and judicial fairness, such kind of deception should be strictly regulated by the law. They should be applied only as the last resort and only on specific targets. Meanwhile, the methods of deception should be strictly limited and can be used only for achieving justifiable objectives. Moreover, once a judicial promise is made to the criminal suspect by investigation or judicial organ, it must be kept. The principle of judicial credit is regarded as one of important principles of criminal justice. |