Real evidence

It is an offense at common law "to tamper with, conceal, or destroy evidence knowing that it may be wanted in a judicial proceeding or is being sought by law enforcement officers."[1] This is also a crime under statutes of many U.S. states.[1] A 2004 review found that 32 states had a statute "that prohibits, in some form, the concealment, destruction, or tampering with evidence."[2] Evidence tampering "generally refers to physical evidence and is not founded on false statements or the concealment of information by false statements."[1] It falls within the broader set of obstruction of justice-related offenses; others include perjury, bribery, destruction of government property, contempt, and escape.[2]

Generally, the elements of the offense are: that the person had "knowledge that an official proceeding or investigation is in progress or is likely to be instituted"; that the person took (2) "overt action to alter, destroy, conceal, or remove evidence"; and that (3) the person had the "purpose of impairing the value or availability of the evidence in the proceeding or investigation."[1]

In Pennsylvania v. Muniz (1990), the U.S. Supreme Court "distinguished 'physical' and 'demeanor' evidence from 'testimonial' evidence, holding that evidence of the former does not engender Fifth Amendment protection" against self-incrimination.[3] The U.S. Court of Appeals for the Ninth Circuit has held that "physical evidence includes one's fingerprints, handwriting, vocal characteristics, stance, stride, gestures, or blood characteristics."[3]