What are the police methods of crime solving

Technical investigation methods refers to the investigation of various types of crime cases, in order to obtain all kinds of intelligence, information, data, etc., by professionals through a special program of the law secretly used by the proprietary technology, methods, means and measures.

(II) criminal technical investigation means

The use of technical investigation means to discover and expose crime, is the world's investigative agencies to fight crime is a common practice.

(C) technical investigation measures

Technical investigation measures, refers to the investigative agencies in order to detect the needs of a particular crime, according to the relevant provisions of the state, after strict approval, to take a specific technical means. Technical investigation behavior is the use of technical investigation measures of investigation behavior. Usually include electronic eavesdropping, telephone listening, electronic monitoring, secret photography, video recording, mail inspection and other secret specialized technical means.

Criminal investigation coercive measures

1 interrogation of suspects

Interrogation of suspects, refers to the investigators in accordance with the legal procedures in order to ask suspects about the facts of the case and other case-related information in a verbal manner an investigative behavior.

Procedures and methods of interrogation of criminal suspects

1, the subject of interrogation

Interrogation of criminal suspects must be carried out by the public security organs or people's procuratorates investigators. In order to improve the efficiency of interrogation, to ensure the quality of interrogation, to prevent lawlessness and to ensure the safety of interrogation, interrogation, the investigators not less than two people.

2. The place of interrogation

(1) After the suspect is sent to the custody of the detention center, the investigator's interrogation of the suspect shall be conducted in the detention center.

(2) A criminal suspect who does not need to be arrested or detained may be summoned to a designated place within the city or county where the criminal suspect is located or to his place of residence for questioning, but a document certifying this shall be produced from the public security organ or the people's procuratorate.

3. Duration of Interrogation

(1) The maximum duration of the summons or detention shall not exceed 12 hours; where the case is significant or complex and detention or arrest measures are required, the duration of the summons or detention shall not exceed 24 hours. Article 195 of the Rules of the High Prosecution provides that the time between two summonses shall not normally be less than 12 hours.

(2) The suspect shall not be detained in disguise in the form of successive summonses and detention summonses.

(3) Criminal suspects who have been detained or arrested shall be interrogated within 24 hours of detention or arrest, and must be released immediately when it is found that they should not be detained or arrested.

4. Steps and methods of interrogation

(1) When interrogating a criminal suspect, the investigator should first interrogate the suspect about whether he or she has committed a crime.

(2) If the suspect admits to having committed a crime, that is, let him or her state the guilty circumstances; if the suspect denies having committed a crime, let him or her state the plea of innocence, and then, according to his or her statement, ask the suspect questions.

(3) The suspect shall answer the investigator's questions truthfully. But he or she has the right to refuse to answer questions that are not related to the case.

(4) interrogation of the suspect shall make a transcript of the interrogation. The transcript shall faithfully record the questions, answers and other people present.

(5) Interrogation of criminal suspects is strictly prohibited to extort confessions by torture, nor is it permissible to induce confessions, lie about confessions, or ask for confessions by name. A suspect has the right to file a complaint against a person who extracts a confession by torture; if this constitutes a crime, he or she shall be held criminally liable in accordance with the law.

5. Interrogation of special criminal suspects

Interrogation of deaf or mute criminal suspects shall be attended by those who are conversant with deaf or mute signs, and this shall be recorded in the transcript. When interrogating a suspect who is a minor, his legal representative may be notified of his presence. If the suspect does not understand the local common language and script, an interpreter shall be provided for him or her.

2 Questioning Witnesses and Victims

Interviewing witnesses refers to the investigator in accordance with the legal procedures to the witnesses in a verbal way to investigate and understand the case of an investigative act.

Procedures for questioning witnesses:

1. Questioning witnesses can only be conducted by investigators. There shall be no fewer than two investigators.

2. Investigators questioning witnesses may be conducted at the witness's unit or residence, but must present documents from the public security organ or the people's procuratorate.

3. The questioning of witnesses shall be conducted individually.

4. In order to ensure that witnesses provide evidence truthfully, when questioning a witness, he should be informed that he should truthfully provide evidence, testimony and intentional perjury or concealment of incriminating evidence to be held legally liable.

5. When questioning a witness who is under 18 years of age, his legal representative may be notified of his presence.

6. When questioning a witness, the witness shall generally be allowed to give a detailed and continuous account of what he knows, and shall be asked about the source of the facts described, and then, on the basis of his or her account and in conjunction with the facts and relevant circumstances of the case that should be determined, the witness shall be asked questions to be answered by him or her.

7. A transcript of the witness's account shall be made and either checked by the witness or read out to him.

3 survey, inspection

Survey and inspection, including survey and inspection. The object of the survey is the scene, objects and corpses, while the object of the inspection is the person, of which the survey includes the scene survey, physical evidence survey and corpse survey.

1, on-site investigation procedures procedures

(1) protect the scene. Any unit or individual, are obliged to protect the scene of the crime, and immediately notify the public security organs to send officers to investigate. After receiving the case, investigators should quickly arrive at the scene of the crime and protect the scene.

(2) The investigator must have a document from the public security organ or the procuratorate when conducting the scene investigation.

(3) If necessary, a person with specialized knowledge may be assigned or hired to conduct the investigation under the auspices of the investigator. Two witnesses unrelated to the case shall also be invited to be present.

(4) investigators at the scene of the investigation, should be timely to the scene around the public, victims, witnesses, informants and other investigative visits, collect, fix and preserve a variety of evidence.

(5) the scene of the investigation shall be made into a record, the investigators, other persons and witnesses to participate in the investigation shall be signed or stamped on the record.

2, the physical examination of the procedural procedures

(1) must be timely, careful, meticulous examination of physical evidence, if the need for specialized technical personnel to test and identification, should be assigned or hired appraisers for identification.

(2) physical evidence should be produced for the examination of transcripts, to participate in the examination of investigators, appraisers and witnesses should be signed or stamped.

3, post-mortem examination procedures

(1) for the cause of death of the body, approved by the person in charge of public security organs at or above the county level, can be autopsied or open casket inspection, and notify the deceased's family members present.

(2) autopsy of the situation, should make a statement, and by the investigators, forensic doctors or physicians to sign or seal.

4, personal examination procedures

(1) the victim, the suspect for personal examination, must be carried out by the investigators. If necessary, under the auspices of the investigator, can also hire a forensic doctor or physician in strict accordance with the law, shall not insult the personality of the person being examined.

(2) Personal examination of the suspect, if necessary, can be mandatory. However, the physical examination of the victim shall not be compulsory. The physical examination of women shall be conducted by a female staff member or a physician.

(3) Physical examination of the situation shall be made a record, and the investigator and the examination of the forensic doctor or physician to sign or seal.

4Search

Search is a coercive method by which the judicial authorities, in order to collect evidence of a crime and to seize the criminal, search and inspect, in accordance with the law, the body, belongings, residence and other relevant places of the accused as well as of those who may hide the criminal or evidence of the crime.

Search procedures:

1. Searches can only be carried out in accordance with the law by the public security organs, the People's Procuratorate and other investigative organs of the investigators, and no other organs, organizations or individuals have the right to search the persons and residences of citizens.

2, the search, there must be more than two investigators, and hold the county level or above, the principal investigative organs issued by the search warrant.

3, any unit or individual is obliged to follow the public security organs and the people's procuratorate's request, hand over can prove the suspect's guilt or innocence of the physical evidence, documentary evidence, audio-visual materials. Otherwise, the investigating authorities may compel extraction in accordance with the law.

4. When searching, the person being searched or his family, neighbors or other witnesses shall be present.

5. The search of a woman's body shall be conducted by a female staff member.

6. A record of the search shall be made and signed or sealed by the investigator and the searched person or his family members, neighbors or other witnesses. If the searched person is at large or his family refuses to sign or seal, it should be noted in the transcript.

Seizure of material 5 evidence, documentary evidence

Seizure of material evidence, documentary evidence, refers to the investigative organs in accordance with the law to force the detention or freezing of goods, documents, money related to the case of an investigative act.

Procedures for the seizure of physical and documentary evidence:

1, check, the investigator shall, together with the witnesses present and the holder of the seized and detained property, documents, seized property, documents, a clear check;

2, list, on the basis of the check, should be listed in duplicate on the spot, in the list, the name of seized and detained property, documents, and the name, specification, characteristics, quality, quantity, and the list of the seized and detained property.

3. Signed and sealed, the list shall be signed or sealed by the investigator, the holder and the witnesses present;

4. Retained, a copy of the list of seizure and detention shall be handed over to the holder or his/her family members, and the other copy shall be attached to the file by the investigating authority for examination. List on the spot, may not be altered, where corrections must be made, there must be investigators, holders and witnesses *** with the signature or seal, or re-open the list.

6 identification

Identification refers to the investigation in order to find out the case, if necessary, let the victim, witnesses and suspects of crime-related objects, documents, bodies, places or suspects to identify a kind of investigative behavior.

Procedures for identification:

1. If the public security organs and the people's procuratorates need to identify the criminal suspects in the course of the investigation of cases under their respective jurisdictions, they shall be approved by the head of the department in charge of the case or by the procurator-general respectively.

2. Identification shall be conducted under the auspices of the investigator.

3, more than one identifier to identify the same identification object, should be identified by each identifier alone. If necessary, witnesses may be present.

4. During the identification, the object of identification shall be mixed with other persons or objects, and no hint shall be given to the identifier.

5. In cases investigated by the public security organs, if the person making the identification does not wish to do so openly, he or she may do so without exposing the person making the identification, and the investigator shall maintain his or her confidentiality.

6. In the case of identification, a transcript shall be made and signed or stamped by the investigator who presides over and participates in the identification, the person who identifies the person, and the witnesses.

7 Wanted

Wanted refers to the public security organs or the people's procuratorate to order the arrest of suspects who should be arrested and is at large a kind of investigative behavior.

Procedures for Wanted:

1. Only the public security organs have the right to issue wanted notices; no other organ, group, unit, organization or individual has the right to do so. People's Procuratorate in self-investigated cases, the need to pursue the fugitive criminal suspects, approved by the Procurator-General, made a wanted decision, notify the public security organs, the public security organs to issue a wanted notice.

2. Public security organs at all levels within the areas under their own jurisdiction.

3. The wanted person must be a criminal suspect who should be arrested according to the law but is at large, including a criminal suspect who has been arrested and escaped while in custody.

4, the wanted person's name, alias, former name, nickname, gender, age, nationality, place of origin, place of birth, place of domicile, place of residence, occupation, identity card number, clothing and physical characteristics and attached to the wanted person's photo, can be attached to the fingerprints and other physical evidence of the photo. In addition to matters that must be kept confidential, should be written to indicate the time and place of the crime and a brief case.

5. After the wanted notice is issued, if new and important circumstances are found, a supplementary notice can be issued. The circular must indicate the number and date of the original wanted notice.

6, the relevant public security organs to receive the wanted notice, should be promptly arranged for the investigation and seizure. Apprehended suspects, shall promptly notify the wanted notice issued by the authorities, and reported to the public security organs above the county level of the place of capture after the approval of the person in charge, with the wanted notice of detention. The original wanted notice issuing authority shall immediately verify and deal with according to law.

7, the wanted person has been returned to the case, death, or the reason for the wanted has disappeared without the need for a warrant, the authority issuing the warrant shall immediately in the original scope of notification of the revocation of the warrant.

Legal Basis

The Criminal Procedure Law of the People's Republic of China

Article 52: Judges, procurators, and investigators must, in accordance with the legal procedures, collect all kinds of evidence capable of confirming the guilt or innocence of a suspect or defendant, and the seriousness of the crime. It is strictly forbidden to extort confessions by torture or to collect evidence by threat, enticement, deception or other unlawful methods, and no one may be forced to prove his or her guilt. Must ensure that all citizens who are related to the case or understand the facts of the case, have the conditions to provide evidence objectively and adequately, in addition to special circumstances, they can be absorbed to assist in the investigation.