Edmond Locard…

Locard studied medicine and Law at Lyon, he eventually became the assistant of Alexandre Lacassagne, a criminologist and professor. He held this post until 1910, when he began the foundation of his crime laboratory. He produced a seven-volume wok - Traité  de Criminalistidue - and in 1918 developed twelve matching points for fingerprint identification. Locard continued his research until his death in 1966.

‘Wherever he steps, whatever he touches, whatever he leaves, even unconsciously, will serve as a silent witness against him. Not only his fingerprints or his footprints, but his hair, the fibers from his clothes, the glass he breaks, the tool mark he leaves, the paint he scratches, the blood or semen he deposits or collects. All of these and more, bear mute witness against him. This is evidence that does not forget. It is not confused by the excitement of the moment. It is not absent because human witnesses are. It is factual evidence. Physical evidence cannot be wrong, it cannot perjure itself, it cannot be wholly absent. Only human failure to find it, study and understand it, can diminish its value. ‘

-Professor Edmond Locard

Documents…

In a many criminal cases, a document examiner provides another type of identification. This type of identification involves written evidence. Other than analysing the handwriting, a document examiner will also determine the age and source of the paper and ink.

Evidence can be found away from the primary crime scene. This is why careful searches are made of a suspects home, vehicle and work place, as well as other sites associated with the suspect.

Firearms…

If a firearm has been used and left at a crime scene the forensic scientists will recover the weapon - take it back to the laboratory and will use chemicals and microscopes to examine the firearm and its projectiles.

When bullets or shell casings are matched to the firearm of a suspect it can be very strong evidence.

Securing the Scene…

Public curiosity can create difficulties and it becomes a significant problem when a murder or other major crime has been committed. Officials needed to secure a crime scene include: police; forensic scientists, firemen, physicians, ambulance personnel and in some cases bomb disposal experts.

The size of a crime scene can vary from: a single room; spread over an extensive area of land.

The job of the first police-officer on the scene - the first officer attending (FOA) - is to help any victims who are alive. If they are injured, they must have medical assistance immediately. The victim should not be cleaned up, not until a forensic officer has checked for trace evidence.

These officers will also detain any possible suspects and eyewitnesses, taking their statements. They should be kept separate from everyone else to avoid trace evidence being transferred. If someone reported the crime, they should be interviewed, detained, and denied any access to the crime scene. This is because perpetrators have been known to report their crime to appear innocent and gain entry in order to confuse the crime scene.

Any crime scene should be sealed off to prevent onlookers contaminating the evidence. The police will cordon off the area usually with tape, and will restrict the areas of access, logging in all visitors and recording what evidence they remove from the crime scene.

Tents are sometimes used to protect the scene from the elements and onlookers.

Every contact leaves a trace…

A crime scene is filled with clues including:

• Fingerprints.
• Hair.
• Blood.
• Fibres.
• Drugs.
• Paint.
• Soil.
• Tyre tracks.

The idea that ‘every contact leaves a trace’ was stated by Dr. Edmond Locard, a French police officer and forensic scientist, in 1920. Ten years earlier had established the world’s first crime laboratory in Lyon, France.

Locard’s concept - known as Locard’s Exchange Principle, is the key to modern forensic science. It means that physical evidence will be exchanged during physical contact between victim and a suspect.

The forensic laboratory is often key to a successful police investigation. Lab results should indicate if a crime was committed, tests can verify evidence that help convict whoever is responsible.