1.When a crime is commeted the first that have to be done is call the police. After call them, tha police will interview possible witnesses or suspects and sign the possible evidences.
2. They immediately call a crime-scene photographer to make a photo of everything which can be important. (phtographs are very important they can be used as evidence in court).
3. Person or people who take something from the crime to be examined. They can be policemen who think that something important has to be examined; and they send possible evidences to laboratory. They can be also a trace-evidence examiner who is the same person examining the evidence and taking it.
4. At the laboratory, the evidences are only examined by trace-evidence examiners who were formed by Cuerpo Nacional de la Policia in this practices and know how to do it in every moment. They have to be policemen or policewomen as well as having a career in relation with biology or chemistry.