Those who employ forensic science solve crimes by using all of the available information about, and evidence from, a crime scene in order to determine who committed it. Forensic scientists from different fields take certain pieces of evidence and make conclusions that form a full picture of what happened at a crime scene. This information is then used by the police and prosecutors to bring a criminal to justice.
Crime scene investigators collect evidence for forensic scientists to later analyze. Evidence found at crime scenes may include blood, hair, fibers, glass and fingerprints. The items are analyzed by different types of forensic scientists depending on the nature of the evidence. For example, blood evidence is examined by forensic serologists; fibers, hair and glass evidence are examined by criminalists; and fingerprint evidence is analyzed by forensic chemists.
In some cases, forensic psychologists and psychiatrists will create profiles of criminals as an additional tool for the police to use in apprehending them. In order to do this, these behavioral scientists will look at all of the available evidence from a crime, which gives them valuable clues about the person who may have committed it. Some of the information included in a profile includes the criminal's possible age, race and marital status.
When investigators arrive at crime scenes, they get information about suspects from any witnesses and living victims who are there when they arrive. Although this can be a useful tool in solving crimes, the memories of eyewitnesses can be unreliable, so forensic scientists will analyze physical evidence to confirm the verbal evidence that was recorded.
Reconstructing a Crime
Forensic science can give investigators information about how a crime was committed---including what weapons were used, when the crime happened and where the crime happened. For example, criminalists can examine shells from a gun to determine what kind of gun was used to commit a crime, and a forensic pathologist can examine a body to determine if a victim had been repeatedly abused.
Evidence that is analyzed by forensic scientists can help identify criminals. Every time we come into contact with an environment, we leave something behind---and crime scenes are no different. Criminals may leave behind ways to identify them, such as blood, semen and hairs that may yield DNA evidence, or fingerprints that can be matched against information that is stored in criminal databases.
Linking Suspect to Victim
Forensic science can also link a suspect to a victim of a crime. If a victim's home happens to have a fingerprint, fibers from a shirt or blood from a criminal, there is a scientific connection between the suspect and the victim. Likewise, if a victim's hair or blood is found in a suspect's home, it also indicates that the suspect and victim had contact.