Locard’s exchange principle The principle states that every criminal will bring something with them when they enter a crime scene and will leave something when they go. The Locard Principle This new principle states that when a person comes into contact with an object or other person, a potential transfer of physical evidence can occur. In crime scene parlance, that means stuff left behind. These trace evidence include hair follicles, to sweat, to skin cells and footwear impression, etc. Not only will a perpetrator leave behind evidence of their presence at the scene, they will also leave with evidence of the scene on them. Locard’s principle states that any contact between two objects results in an exchange. Known as the Locard Exchange Principle, after Dr. Edmond Locard, the French police officer who first noticed it, the exchange of materials is the basis of modern forensic investigation. Locard's Exchange Principle states that with contact between two items, there will be an exchange…  Due in no small part to Mr. Bertillon's influence, it was Dr. Locard's belief and assertion that when any person comes into contact with an object or another person, a … If you own a pet, this material exchange is […] Every contact you make with another person, place, or object results in an exchange of physical materials. Locard's principle applies to law enforcement and the investigation of crime scenes directly. Professor Edmond Locard's famous theory of exchange can be summed up as as "every criminal leaves a trace".Locard said, in his 1934 publication "La police et les methodes sceientifiques":"Any action of an individual, and obviously, the violent actions of a crime, cannot occur without leaving a trace." Introduction Locard’s exchange principle states that “every contact leaves a trace” indicating that trace evidence left by the perpetrator will always be found in the scene of crime (1). Locard's work formed the basis for what is widely regarded as a cornerstone of the forensic sciences, Locard's Exchange Principle, which states that with contact between two items, there will be an exchange. Good news for cops and prosecutors, bad news for cri The Locard's Exchange Principle states that ''with _____ between two items, there will be an _____." Edmond Locard (1877–1966) French professor Considered the father of criminalistics Built the world’s first forensic laboratory in France in 1910 Locard Exchange Principle: Whenever two objects come into contact with each other, there is always a transfer of material. First recognized by Doctor Edmond Locard, this Principle has been used by crime scene investigators for almost a century now. Although Locard's exchange principle is generally understood as the phrase "with contact between two items, there will be an exchange," Edmond Locard never actually wrote down those words in the vast amount of material he produced, nor did he mention anything concerning a principle. Locard's Exchange Principle is very straightforward, asserting that with contact between two items, an exchange will be made. It was Locard's assertion that when any person … Locard's exchange principle, which states that when two objects come into contact, there is an exchange of material; Skid mark; Digital traces; Blowback, material drawn into the barrel of a … Locard's Theory - the Principle of Exchange.