It is known as physical evidence.
Hairs
Hair. It can be left behind by a suspect and used as evidence to link them to a crime scene through DNA analysis.
Hairs
DNA evidence found at the crime scene can be compared to the suspect's DNA to determine if there is a match, providing a strong link between the suspect and the crime scene. Other evidence such as fingerprints, footprints, or personal belongings left at the scene can also help link a suspect to a crime. Eyewitness testimony or surveillance footage placing the suspect at the scene can further establish their connection.
this may show if someone shot a gun
Yes, there is the primary crime scene and the secondary crime scene. For example, if a body was found in a trash can but there is no evidence that the person was killed there then it means the person was killed somewhere else. The primary crime scene is where the person was killed and the secondary crime scene is where the body was dumped.
A bystander is a person who is present at an incident or event, but does not participate. An example is someone that may have seen a crime scene or a spectator at an event.
There is actually no set number as to how many finger prints are got from a crime scene. There are cases where the criminal is a pro and does not leave even one full finger print and there are cases where the criminal is a novice or someone is being framed where multiple prints are found.
Criminals may return to the scene of the crime due to a psychological need for closure, a desire to relive the experience, or to ensure that their crime was successful. Additionally, returning to the scene may provide a sense of power or control over the situation.
There are many colleges which offer courses in becoming a crime scene investigator, and some jurisdictions only require the completion of one of these courses. However, some jurisdictions require that crime scene investigators be active police officers first. You may have to speak with someone in your local police department to find out what their requirements are.
It is strong physical evidence. It places the person at the crime scene. The person may have been identified through fingerprint evidence and that may be the only way to link the person to the crime scene. Through fingerprints you are able to determine a person's identity. Eye-witnesses can be wrong, fingerprints don't lie.
A'crime scene technician' and a Crime Scene Investigator (CSI) are just different terminology used for the same job. they are specialists whose duties it is to gather the evidence at the scene of the offense and preserve it in such a way as to make it usable as evidence. The 'technician' may, or may not, be a sworn officer.