Rules of Evidence, What Are They?

A law enforcement officer must know laws, specific elements, and the Rules of Evidence. What are the Rules of Evidence in America’s legal system?

The American legal system depends on the admissibility of Evidence.

Consequently, Evidence is crucial in both criminal and civil proceedings. The Evidence covers the burden of proof, relevance, admissibility, weight, and sufficiency of what should be admitted into the record of a legal proceeding.

All Evidence to be admitted in court must be legally obtained. Therefore, any additional Evidence obtained illegally is not permitted. Such Evidence is called “The fruit of the poisonous tree.”

The fruit of the poisonous tree is an extension of the exclusionary rule. The exclusionary rule requires that illegally obtained Evidence be excluded from a criminal trial admission. The fruit of the poisonous tree takes the assessment one step further by excluding Evidence that stemmed from the poisonous tree’s primary illegality.

For example, if there is an illegal interrogation that leads to physical Evidence, the exclusionary rule prohibits the introduction of the interrogation in the criminal trial.

Additionally, physical Evidence is excluded because it is the fruit of the illegal process. Similarly, if law enforcement coerced a confession in which the criminal defendant said where a weapon used in a crime was located, and law enforcement obtained a search warrant based on this confession, the weapon would be inadmissible because it would be the fruit of the poisonous tree. Likewise, the confession would also not be admissible.

The purpose behind this doctrine is to deter police misconduct. Therefore, the original illegal Evidence is considered the poisonous tree, and any evidence that stems from this tree is similarly tainted.
Exculpatory Evidence is Evidence in a criminal trial that shows that the defendant is not guilty.

A defendant is charged with a crime, and both the prosecutor and defense attorney gather Evidence to each make their case. If the prosecutor comes across any evidence that shows the defendant didn’t commit the crime, they have to turn it over to the defense. If the prosecutor neglects this step, then the case can be dismissed, retried, or even the defendant found not guilty.

There are five types of Evidence applicable in a criminal case. They are Real Evidence, Demonstrative Evidence, Testimonial Evidence, Documentary Evidence, and Digital Evidence.

Real Evidence is anything present or used at the time and location of the crime. Demonstrative Evidence is used in addition to testimonies. It backs up to prove the case right or wrong. Examples are diagrams, animations, maps, and other similar additions. Testimonial Evidence is the most direct form of Evidence presented. It involves the statements of witnesses of what they saw before, during, and after the crime.

Documentary Evidence may be presented as part of real Evidence.

This Evidence is any evidence that builds up the documentation of events leading to the crime. Digital Evidence is any digital file or electronic source. Examples may be text messages, emails, phone calls, documents, and data obtained from hard drives.

Other forms of Evidence are Circumstantial, Corroborating, and Hearsay. Circumstantial Evidence tends to prove a factual circumstance by proving other events from which the incident can be reasonably concluded.

Corroborating is independent and other Evidence but supports and strengthens Evidence presented as proof of the facts. Hearsay is a statement made out of court, not under oath, which is presented as proof that what was testified is true. (Usually inadmissible)

The defense will almost always challenge confessions. If successful, the admission and any evidence obtained from the confession will be inadmissible. The investigation must continue by collecting additional Evidence as if a confession was never received.

A longtime columnist and man of faith, Keith Throckmorton, Fairfax County Police (Ret), can be reached at