The formation of evidence chain emphasizes the need to form a closed-loop chain between the key evidences that identify the facts of the case. As a public security investigation organ, it is necessary to collect evidence extensively in the process of solving crimes. Only when the collected witness testimony and trace material evidence are connected and combined in an orderly manner to form the main link of the criminal suspect's crime can we judge the criminal facts of the criminal suspect and take necessary criminal investigation measures.
As for the evidence chain is not closed, for a simple example, the police found A's body, and there is reason to suspect that the murderer may be the husband of the deceased. The murder weapon was a fruit knife in their house, and the fingerprints on it were highly consistent with those of her husband B, but she denied killing A and provided an alibi. At this time, the police only obtained B's fingerprint from the fruit knife, which is not enough to prove that B killed A. Because the fruit knife is a common item at home, it is normal to leave B's fingerprint, so the evidence chain is not closed. The police need to collect other powerful evidence to prove and restore B's criminal facts and motives, such as finding counter evidence to overthrow B's alibi.
legal ground
Article 48 of the Criminal Procedure Law stipulates that all materials that can be used to prove the facts of a case are evidence. Evidence includes:
(1) Physical evidence;
(2) Documentary evidence;
(3) Testimony of witnesses;
(4) the victim's statement;
(5) confessions and excuses of criminal suspects and defendants;
(6) Appraisal opinions;
(7) Records of the inquest, inspection, appraisal, investigation and experiment;
(8) Audio-visual materials and electronic data.
The evidence must be verified before it can be used as the basis for finalizing the case.