Real and Demonstrative Evidence

In a criminal trial, evidence is essential to establish the defendant's guilt or innocence.

This article focuses on two types of evidence:

• Real evidence
• Demonstrative evidence

Real and demonstrative evidence are two crucial forms of evidence, subject to the Federal Rules of Evidence (FRE). State laws may vary slightly, but state rules of criminal procedure are based on the same principles.

Types of Evidence Used At Trial

There are four types of evidence used to prove or disprove facts at trial:

• Real evidence
• Demonstrative evidence
• Documentary evidence
• Testimonial evidence

We'll discuss real and demonstrative evidence in more detail below.

Documentary Evidence

Documentary evidence includes evidence found in documents. Documentary evidence includes direct evidence and circumstantial evidence.

Some examples of documentary evidence include, but are not limited to, the following:

• Letters
• Contracts
• Newspapers
• Family Bible
• Last Will and Testament
• Deposition transcript

Testimonial Evidence

When someone gets up on the stand at trial and relates something they saw or heard, that is testimonial evidence. It is a witness giving testimony under oath about the facts of the case. If that witness is an expert, they provide expert testimony.

Not all of these types of evidence carry the same weight at trial. For instance, real evidence may be more believable than demonstrative evidence. The jury's role is to weigh each type of evidence and determine its meaning in the case.

Real Evidence

Real evidence, often called physical evidence, consists of material items. This includes objects and things the trier of fact (jury or judge) can physically hold and inspect.

Examples of real evidence include the following:

• Fingerprints
• Footprints
• Blood samples
• DNA
• X-rays
• Murder weapon
• Clothing
• Narcotics
• Videotapes
• Crime scene photos
• Police bodycam footage
• Security footage

Under the Federal Rules of Evidence, real evidence should be relevant, material, and authenticated. In this context, material means important to the outcome of the case.

Laying a Foundation: Term Explained

Attorneys establish these characteristics by "laying a foundation." Laying a foundation is a legal term of art that refers to establishing the authenticity of evidence.

Consider DNA results from a blood sample collected from a crime scene. The attorney may call the law enforcement officer who collected the sample to testify and establish the chain of custody. Chain of custody is another term of art that refers to all of the people who handle a piece of evidence.

Ideally, the officer followed proper procedure in handling the sample and took it directly to the crime lab. The proper procedure often includes documenting every step, from the collection of the sample to delivering it to the crime lab.

Demonstrative Evidence

Demonstrative evidence should demonstrate or illustrate the testimony of a witness. The admissibility of demonstrative evidence is contingent on whether it fairly and accurately reflects the witness's testimony and is more probative than prejudicial.

The following is a non-inclusive list of demonstrative evidence examples:

• Maps
• Exhibits that demonstrate harm or loss suffered by a party to the case
• Crime scene diagrams, such as blood splatter
• Graphs and charts

Expert witnesses often create and use demonstrative evidence at trial. Opposing counsel may use the same evidence to prove their position.

Admissibility of Evidence

Attorneys can only use admissible evidence at trial. The admissibility of evidence depends on more than authenticity and materiality. The prejudicial potential of the evidence cannot outweigh its probative value. Prejudicial potential refers to the possibility that the judge or jury may reach an improper conclusion based on a piece of evidence. 

For example, in a murder trial, the court may exclude gruesome photos of the murder as being prejudicial to the defendant. The prosecution may use less gruesome photos to establish the cause of death.

Probative value refers to the ability of a piece of evidence to prove or disprove facts.

The difficult admissibility questions arise when:

• The probative value is low
• The prejudicial potential is high
• The law requires the use of the evidence to prove an element of a criminal charge

For example, FRE 609 allows the government to impeach the defendant's testimony with evidence of prior bad acts. These bad acts may include prior convictions, including convictions for crimes like the one for which the defendant is currently on trial. After hearing about these bad acts, juries may no longer be able to keep an open mind.

This presents a problem for defendants who want to testify on their own behalf. Under FRE 403, the court can exclude relevant evidence if the danger of unfair prejudice substantially outweighs its probative value. Similarly, FRE 403 allows for exclusion to avoid substantial danger of undue prejudice.

Questions About Real and Demonstrative Evidence? Talk to an Attorney.

Understanding the Federal Rules of Evidence is a challenging task. An excellent criminal defense attorney understands these rules and knows how to apply them. They can gather and evaluate real and demonstrative evidence for use at trial. If you are facing criminal charges, you should speak to an experienced local criminal defense attorney today.