Could be - perpetrator, victim, witness or accomplice.
Yes, there can be more than one crime scene associated with a single crime. Different locations may be involved in the commission of a crime, such as where evidence is found or where different parts of the criminal act occurred. Each crime scene may provide valuable information for investigators in piecing together the sequence of events.
They are known as crime scene investigator/examiner, crime scene photographer, crime photographer.
To the best of my knowledge the professional person who investigates a crime where it was perpetrated is called "a crime on scene investigator".
A piece of fingernail found at the crime scene
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.
recover it from a person or crime scene
Hair found at a crime scene contains DNA, which can be compared to a suspect's or victim's DNA to establish a link. Hair also has unique characteristics like color, length, and treatment, which can be used as evidence in investigations. Analyzing hair evidence can help to identify individuals present at the crime scene.
They are called the Coroner.
The henchmen were subdued with the help of the police present at the crime scene.
The crime scene investigators use the biotechnology and genetis technology for solving their case. They collect every sample from the crime scene and perform the laboratory tests on it which gives them clue about what would have happened on the crime scene and then DNA and the fingerprints are used to prove the identity of the person associated with crime scene
the FAO (first attending officer) is first on the scene when called to a crime.
Determine the extent of injuries to the victims, if any, and summon medical assistance. If no victims present - preservation of the crime scene pending the arrival of detectives and/or evidence techs.