The ability to gather and analyze different types of evidence is one of the most important competencies for anyone who conducts investigations. There are many types of evidence that help the investigator make decisions during a case, even if they aren’t direct proof of an event or claim.
To download a quick reference to the types of evidence outlined in this article click on: Understanding Types of Evidence.
The first rule is that evidence must be relevant to the investigation. If it is not directly related to the case it isn’t relevant evidence. That said, there are many types of evidence that, while not admissible in court, can be valuable to an investigator trying to reach a conclusion in a workplace investigation or other non-criminal investigation. And even some evidence that is not admissible on its own may be admissible in conjunction with other types of evidence.
1. Analogical Evidence
While not a kind of evidence you’d use in court, this kind of evidence can be useful for increasing credibility by drawing parallels when there isn’t enough information to prove something in a workplace investigation. Analogical evidence uses a comparison of things that are similar to draw an analogy.
2. Anecdotal Evidence
Anecdotal evidence isn’t used in court, but can sometimes help in a workplace investigation to get a better picture of an issue. The biggest problem with this kind of evidence is that it is often “cherry picked” to present only anecdotes that support a particular conclusion. Consider it with skepticism, and in combination with other, more reliable, kinds of evidence.
3. Character Evidence
This is a testimony or document that is used to help prove that someone acted in a particular way based on the person’s character. While this can’t be used to prove that a person’s behavior at a certain time was consistent with his or her character, it can be used in some workplace investigations to prove intent, motive, or opportunity.
4. Circumstantial Evidence
Also known as indirect evidence, this type of evidence is used to infer something based on a series of facts separate from the fact the argument is trying to prove. It requires a deduction of facts from other facts that can be proven and, while not considered to be strong evidence, it can be relevant in a workplace investigation, which has a different burden of proof than a criminal investigation.
Need a tool for tracking and reporting on your investigation and the evidence you collected? Download our free Investigation Report Template.
5. Demonstrative Evidence
An object or document is considered to be demonstrative evidence when it directly demonstrates a fact. It’s a common and reliable kind of evidence. Examples of this kind of evidence are photographs, video and audio recordings, charts, etc. In a workplace investigation, this could be an audio recording of someone’s harassing behavior or a photograph of offensive graffiti.
How to Record Digital Evidence with Camtasia Screencasting Software
6. Digital Evidence
Digital evidence can be any sort of digital file from an electronic source. This includes email, text messages, instant messages, files and documents extracted from hard drives, electronic financial transactions, audio files, video files. Digital evidence can be found on any server or device that stores data, including some lesser-known sources such as home video game consoles, GPS sport watches and internet-enabled devices used in home automation. Digital evidence is often found through internet searches using open source intelligence (OSINT).
OSINT is one of the most efficient ways to gather digital evidence online. Search online using this comprehensive link list of OSINT tools and resources.
Challenges of digital evidence
Collecting digital evidence requires a skillset not always needed for physical evidence. There are many methods for extracting digital evidence from different devices and these methods, as well as the devices on which evidence is stored, change rapidly. Investigators need to either develope specific technical expertise or rely on experts to do the extraction for them.
Preserving digital evidence is also challenging because, unlike physical evidence, it can be altered or deleted remotely. Investigators need to be able to authenticate the evidence, and also provide documentation to prove its integrity.
7. Direct Evidence
The most powerful type of evidence, direct evidence requires no inference. The evidence alone is the proof. This could be the testimony of a witness who saw first-hand an incident of sexual harassment in the workplace.
8. Documentary Evidence
Most commonly considered to be written forms of proof, such as letters or wills, documentary evidence can also include other types of media, such as images, video or audio recordings, etc.
9. Exculpatory Evidence
This type of evidence can exonerate a defendant in a – usually criminal – case. Prosecutors and police are required to disclose to the defendant any exculpatory evidence they find or risk having the case dismissed.
10. Forensic Evidence
Forensic Evidence is scientific evidence, such as DNA, trace evidence, fingerprints or ballistics reports, and can provide proof to establish a person’s guilt or innocence. Forensic evidence is generally considered to be strong and reliable evidence and alongside helping to convict criminals, its role in exonerating the innocent has been well documented. The term “forensic” means “for the courts”. Its use in workplace investigations is generally limited to serious cases that may end up in court.
11. Hearsay Evidence
Hearsay evidence consists of statements made by witnesses who are not present. While hearsay evidence is not admissible in court, it can be relevant and valuable in a workplace investigation where the burden of proof is less robust than in court.
12. Physical Evidence
As would be expected, evidence that is in the form of a tangible object, such as a firearm, fingerprints, rope purportedly used to strangle someone, or tire casts from a crime scene, is considered to be physical evidence. Physical evidence is also known as “real” or “material” evidence. It can be presented in court as an exhibit of a physical object, captured in still or moving images, described in text, audio or video or referred to in documents.
13. Prima Facie Evidence
Meaning “on its first appearance” this is evidence presented before a trial that is enough to prove something until it is successfully disproved or rebutted at trial. This is also called “presumptive evidence”.
14. Statistical Evidence
Evidence that uses numbers (or statistics) to support a position is called statistical evidence. This type of evidence is based on research or polls.
15. Testimonial Evidence
One of the most common forms of evidence, this is either spoken or written evidence given by a witness under oath. It can be gathered in court, at a deposition or through an affidavit.