A forensic evidence collection kit is a professional combination of tools used for collecting, preserving, and transporting various types of forensic evidence. Its specific applications are as follows:

Evidence Collection at Crime Scenes

• Collection of Biological Samples
  • Blood Samples: Use sterile blood collection needles and tubes to collect blood, which can be used for DNA analysis, blood type identification, etc. For example, at a homicide scene, if the bloodstains of the victim or suspect are found, they can be collected using blood collection tools and taken back to the laboratory for analysis, and then compared with the DNA of known individuals to determine their identities or connections.
  • Hair Samples: Use tweezers or hair collection devices to collect hair. The morphology, color, and hair follicles of the hair can serve as evidence, and the DNA in the hair follicles can also help with identification. For instance, in a sexual assault case, the suspect’s hair may be found on the victim’s clothing or at the scene.
  • Saliva Samples: Collect saliva through saliva collectors, from which oral epithelial cells can be obtained for DNA testing. For example, in some cases involving bite marks, the suspect’s saliva may be collected from the bite mark.
• Collection of Physical Evidence
  • Fiber Samples: Use adhesive tapes or tweezers to collect fibers at the scene, such as clothing fibers, carpet fibers, etc. Fibers of different materials and colors may be related to the clothing of the suspect or the victim, or the scene environment, which helps to determine the location of the crime or the suspect’s range of activities.
  • Fingerprint Collection: Use fingerprint powder and fingerprint brushes, or chemical reagents such as ninhydrin to reveal fingerprints, and then extract them with transparent adhesive tapes or fingerprint collection cards. Fingerprints are very important individual identification evidence, which can directly link the suspect to the crime scene.
  • Collection of Trace Evidence: Use microscope slides and cover slips to collect trace evidence such as soil, glass fragments, paint chips, etc. These substances may adhere to the suspect or the victim, or be left at the scene, providing clues for the case investigation.

Evidence Collection during Autopsy

• Collection of External Evidence
  • Measurement and Recording of Wounds: Use rulers, protractors, and other tools to measure the length, depth, angle, etc. of the wounds, and accurately record the location and shape of the wounds, which is helpful for analyzing the tool used in the crime and the modus operandi.
  • Observation and Recording of Livor Mortis: Use cameras or drawing tools to record the location, color, and extent of livor mortis. The condition of livor mortis can help infer the time of death and the position of the body at the time of death.
  • Collection of Foreign Objects: Use tweezers or cotton swabs to collect foreign objects on the surface of the body, such as soil, leaves, fibers, etc. These foreign objects may be related to the crime scene or the suspect.
• Collection of Internal Evidence
  • Collection of Tissue Samples: Use anatomical instruments to collect samples of tissues and organs such as the heart, liver, lungs, and brain, which are used for pathological examination to determine the cause of death and to judge whether there is poisoning, disease, etc.
  • Collection of Body Fluid Samples: Use syringes or puncture needles to collect body fluid samples such as blood, urine, and cerebrospinal fluid, and test whether there are drug or toxic substances in them, and analyze the alcohol content, etc.

Preparation before Laboratory Analysis

• Preservation and Transportation of Samples
  • Preservation: Use special preservation solutions and containers to preserve biological samples and physical evidence. For example, DNA preservation solutions can prevent DNA degradation, and sterile sealed bags can preserve hairs, fibers, and other physical evidence to maintain their original state.
  • Transportation: Put the collected samples into a special transportation box to ensure that the samples are not damaged, contaminated, or deteriorated during transportation, and ensure that they can still be accurately analyzed and tested after being transported to the laboratory.
• Marking and Recording of Evidence
  • Marking: On each sample container and physical evidence collection bag, use a waterproof marker pen or label to clearly mark information such as the sample source, collection time, and collection location to avoid confusion and errors.
  • Recording: Use evidence collection lists and record sheets to record in detail the collection situation of each piece of evidence, including the collector, collection method, description of the sample appearance, etc., to form a complete record of the evidence chain.