Collecting the evidence - Types of evidence

When it comes to investigating the crime scene, there are different types of evidence that the investigation team will collect from that scene. These types of evidence would be; biological evidence, chemical evidence, physical evidence and evidence involved in the case for example witness statements or surveillance videos.

Biological evidence is evidence belonging to an individual or left at the crime scene from an individual. This could be blood, saliva, semen or any bodily fluids. These different types of evidence can be match to an individual if they have a sample to compare it to. Biological evidence can be a strong piece of evidence that can be used in an investigation if the team have a sample of an individual to match it to. Biological evidence may unknowingly be left at the scene by a suspect for example their fingerprint may be left on a window where they entered to crime scene. 

Chemical evidence is evidence that has chemical compounds and chemical compositions. A type of chemical evidence could be drugs, poison or gunshot residue. An example of chemical evidence at a crime scene would be an accelerant that the suspect has used to try and cover up the crime scene and destroy any evidence.

Physical evidence is a material object that plays a role in the matter. This could be a weapon, a footwear mark or even a vehicle involved in the crime. A physical piece of evidence that may be found at the crime scene which the investigation team would collect could be the murder weapon. This could be a knife or gun for example.

In the Madeleine McCann case there was only biological evidence collected from the apartment of where she disappeared from. This evidence was fingerprints. Although when collecting this biological piece of evidence the police did not wear any PPE, this piece of evidence was still sent to Britain for an analysis. Collecting biological evidence within a case can be beneficial to a certain extent. Biological evidence is a strong piece of evidence if the police have a suspect to match that piece of evidence for example, if they find fingerprints at a crime scene and they have a suspect in custody, they can take fingerprint impressions of the suspect and try matching these to the fingerprints they collected from the crime scene. But if there are no samples to match the evidence to, the police can’t make a match. In this case, the police had suspects of which the fingerprints found in the apartment did not match to. The collecting of this evidence was beneficial as to ruling the suspects they had suspicions of but the police now have no suspects and therefore they can’t use these fingerprints to match to.