Even in those cases in which suspects are immediately seized and the motives and circumstances of the crime readily apparent, it is imperative that a thorough search for physical evidence be conducted at once. Evidence collectors may choose to subdivide the scene into segments and search each segment individually, or the search may start at some outer point and gradually move toward the center of the scene in a circular fashion. What to search for will be determined by the particular circumstances of the crime. Obviously, the skill of crime-scene investigators at recognizing evidence and searching relevant locations is paramount to the successful processing of the crime scene. While training will impart general knowledge for conducting a proper crime-scene investigation, ultimately the investigator must rely on experience gained through numerous investigations to formulate a successful strategy for recovering relevant physical evidence at crime scenes.
Physical evidence can be anything from massive objects to microscopic traces.
Often, many items of evidence are obvious in their presence, but others may be detected only through examination in the crime laboratory. For this reason, it is important to collect possible carriers of trace evidence in addition to more discernible items. The search for physical evidence must extend beyond the crime scene to autopsy room of a deceased victim. Head and pubic hairs. Recovered bullets from the body.