How to investigate the scene of a criminal crime

On-the-spot investigation refers to the investigation and investigation of the crime scene, its traces and other physical evidence by the investigation organ (see the crime scene). The purpose is to find and collect evidence such as criminal traces, understand and study the criminal behavior and the nature of the case, determine the direction and scope of investigation, and provide clues and evidence for the investigation and trial of the case.

Field trips include field trips, investigation visits and data collation;

On-the-spot investigation shall, according to the specific circumstances of the case, delimit the scope of investigation (including the place where the criminal incident occurred and all places with traces and items suspected to be related to the criminal incident) and determine the order of investigation. Exploration can be carried out along the route of criminals entering and leaving the scene, from the center to the periphery or from the periphery to the center, and sometimes it can be carried out in sections or along the boundaries of topography and features.

After determining the scope and sequence of exploration, photos should be taken on the spot. Take azimuth photos and panoramic photos first, and then take center photos and detailed photos with the development of exploration work (see criminal photography).

There are two ways of field exploration: static exploration and dynamic exploration. Static investigation is to observe all the changes caused by criminal acts on the scene, observe the position, state and relationship of various objects and traces, but it is not allowed to touch any objects or traces or change their positions. Dynamic exploration is to inspect the traces or items suspected to be related to the incident one by one without destroying the traces. When necessary, we can turn the moving object upside down and observe it under different lighting angles, or further discover traces and subtle physical evidence through various technical means, so as to study the reasons for the formation of various traces, the state of various physical evidence and the relationship with criminal acts. In the process of dynamic exploration, traces and objects with evidential value must be photographed in proportion, and their positions in the surrounding environment must be photographed. Static exploration and dynamic exploration are two interrelated steps to explore each group or each group of traces and objects, rather than two completely independent stages to explore the whole site.

Investigation visit

At the same time of on-site investigation, personnel must be assigned to investigate and visit the victims, witnesses, people who found the case and on-site protection personnel to understand the time, course and other relevant circumstances of the incident. In some cases, the victim had contact with the criminal, so the physical characteristics, clothing characteristics and escape direction of the criminal should be investigated in detail; If the property is stolen or robbed, you should know the quantity and characteristics of the property. The combination of the materials obtained from the investigation and the materials obtained from the on-site investigation can confirm and complement each other, reflect the overall situation of the site and provide reliable basis for correctly judging the case.

According to different objects, different methods are adopted to conduct field visits. During the interview, the interviewee should not only state all the information he knows, but also explain the source of the interviewee's understanding, the interviewee's daily performance, whether his hearing and vision are normal, and the relationship with the victim. , so as to make a correct judgment on the interviewee's statement.

Site visits should be recorded. Interviewer and interviewee should sign the record.

Rules for on-the-spot investigation The on-the-spot investigation is usually carried out by investigators of public security organs. When investigators think it is necessary, they can invite people with specialized knowledge to assist them. On-site investigation must hold the certificate of the public security organ. When examining a case, the people's procuratorate deems it necessary to re-examine and review the inquest and inspection of the public security organ, it may request the public security organ to re-examine and review the case, and may send procurators to participate. When necessary, the people's court may also conduct an inquest and inspection on the site. All personnel involved in exploration must obey the unified command and strictly abide by the exploration discipline. Two impartial witnesses unrelated to the case must be invited to testify in the on-site investigation. The traces and articles found and extracted shall be witnessed and signed on the exploration record.