• A fingerprint can help identify a suspect.fingerprint image by dip from Fotolia.com
  
  Crime laboratories combine detective work with scientific analysis to reveal details about a crime that would otherwise go unnoticed. Crime laboratories often have workers who specialize in specific areas, such as collecting evidence at the crime scene or using forensic-analysis techniques in the laboratory to learn more about the gathered evidence.
  
  

Latent Prints

• An important part of a crime laboratory's job is to recover latent fingerprints. Since every human has a unique fingerprint, a print can reveal who was at a crime scene. Crime-scene investigators work in concert with their colleagues in the lab to locate fingerprints. One technique they use is "dusting," which refers to sprinkling special dust over an area or on a piece of evidence. The dust sticks to oil left behind from the touch of a human finger. The investigator can then "lift" the fingerprint pattern by placing adhesive tape over the dust. The crime lab can compare the prints to a database of potential suspects in order to identify the perpetrator.
  
  

DNA Analysis

• Human DNA left on at a crime scene can also tell investigators who was present at the time of the crime. Often the crime-scene investigators gather anything that might be a potential source of DNA--a hairbrush or a used glass, for example. Back in the laboratory, technicians examine the objects gathered by the crime-scene investigators. If they find DNA, they can compare it to a database of known offenders or use the information to help corroborate or disprove the story of a potential suspect.
  
  

Chemical Analysis

• Fires and bombs leave chemical residues. Identifying these residues can help narrow down the types of materials used. This information may lead investigators to the perpetrators. Forensic-analysis techniques in the laboratory help identify the chemicals and build a time line of how the event took place.
  
  

Body Analysis

• Crime-laboratory technicians can reveal much about the way a person died, from the time of death to the exact way the person was killed. Crime labs also help to identify a victim, who may be unrecognizable due to the nature of the crime or the length of time since death. One technique they use to identify a body is called forensic facial imaging. By using sophisticated computer programs to determine the likely appearance of a victim based on such features as bone structure and hair color, a crime lab can provide case investigators with a picture of the victim's face. The case investigators can then use the picture to help identify the victim.