Physical evidence generally refers to objects found at a crime scene that establish that a crime has been committed. These objects provide a link between a crime and the victim or a crime and the perpetrator. Examples of physical evidence include guns, weapons, bodily fluids, a bloody knife or shirt, fired bullets, or spent casings. Physical evidence also includes DNA, fingerprints, footprints or lipstick impressions left on a glass or napkin. Physical evidence is a key component in solving crimes.