The Forensic Evidence Collection Kit plays a crucial role in many aspects such as crime scene investigation and forensic identification.

1. Biological Evidence Collection

• Blood Sample Collection:
  The disposable blood collection needles and tubes in the kit can be used to collect blood found at the crime scene. For example, in cases of murder or violent assault, the blood of the victim or the suspect may be left at the scene. The blood collection tools can collect blood samples safely and aseptically, and these samples are crucial for subsequent tests such as blood type identification and DNA analysis. By analyzing the DNA in the blood, the identity of an individual can be determined, the suspect can be linked to the crime scene, or innocent people can be excluded from suspicion.
• Saliva Sample Collection:
  Evidence containing saliva is also quite common at the crime scene, such as cigarette butts and bite marks. The swabs in the kit can effectively collect saliva. In sexual assault cases, saliva samples can be collected from the bite marks on the victim’s body, or in theft cases, saliva can be collected from cigarette butts at the scene. After being processed, these samples can be used to identify the person who left the saliva through DNA testing, providing clues for the detection of the case.
• Hair and Skin Cell Collection:
  Tweezers are an important tool for collecting hair. The hair found at the crime scene may come from the victim or the suspect. The hair root contains hair follicle cells, which are rich in DNA information. Use tweezers to carefully collect the hair and ensure that the hair follicle part is intact for DNA analysis. Meanwhile, for the collection of skin cells, the adhesive swabs in the kit can be used to wipe the surfaces of objects where skin cells may remain, such as door and window handles and weapons at the crime scene. These skin cells can also be used for individual identification.

2. Trace Evidence Collection

• Fingerprint Collection:
  There are various types of fingerprint powders and fingerprint brushes in the kit. On the surfaces of objects made of different materials, such as glass, metal, and plastic, investigators can use appropriate fingerprint powders and brushes to develop and collect fingerprints. For example, on the window glass at a theft scene, by brushing on fingerprint powder, potential fingerprints can be developed. Then, use transparent tape to extract and fix the fingerprints on a card for subsequent fingerprint comparison. Fingerprints are one of the most common trace evidences at the crime scene and can directly point to the suspect.
• Footprint Collection:
  Tools such as plaster powder and footprint molds are included. At outdoor crime scenes, footprints left in soil, sand, or snow can be collected by pouring plaster. First, set up the mold around the footprint, then mix the plaster powder with water and pour it into the mold. After the plaster solidifies, the footprint model can be completely extracted. These footprint models can provide information such as the shoe size and sole pattern of the suspect, helping the police to track the suspect or determine his or her activity track at the crime scene.
• Tool Mark Collection:
  When a crime involves the use of tools, such as crowbars and knives, the silicone rubber materials in the kit can be used to make models of tool marks. Apply the silicone rubber to the tool marks, and after it solidifies, the shape and characteristics of the tool marks can be accurately replicated. These models are of great value in analyzing the type and brand of the crime tool and whether it matches the tool held by the suspect.

3. Trace Evidence Collection

• Fiber Collection:
  Tape and microscope slides are provided. At the crime scene, investigators can use tape to pick up fibers from the clothes of the victim, the suspect’s clothes, or the surfaces of other objects. These fibers may come from the carpet, curtain, packaging of the crime tool, etc. at the crime scene. Transfer the picked-up fibers to the microscope slides, observe the characteristics such as the color, shape, and material of the fibers through a microscope, and compare them with fibers from known sources to determine the source of the fibers and provide clues for the case.
• Paint and Coating Fragment Collection:
  Small tweezers and plastic containers are used to collect paint and coating fragments. In traffic accidents or criminal cases involving building damage, there may be fragments of vehicle paint or building coating left behind. Use tweezers to carefully collect the fragments into plastic containers. These fragments can be analyzed chemically to determine their composition, color, brand, etc., helping the police to identify the involved vehicle or building or match them with the paint on the suspect’s tools or vehicles.
• Glass Fragment Collection:
  Tweezers and special glass collection containers are also used. In criminal scenes involving glass breakage, such as burglary or vehicle collision, it is very important to collect glass fragments. The physical and chemical properties of glass fragments, such as refractive index and composition, can be analyzed by professional instruments and compared with glass from known sources to determine whether they come from the windows at the crime scene, vehicle windshields, etc., thus providing evidence for the case investigation.