Illinois Law Enforcement Training and Standards Board (ILETSB) Practice Exam

What level of evidence is necessary for making an arrest?

1. Reasonable suspicion

2. Probable cause

3. Substantial evidence

4. Preponderance of evidence

The correct answer is: Probable cause

The appropriate level of evidence necessary for making an arrest is probable cause. This standard refers to a reasonable belief, based on facts and circumstances, that a person has committed a crime. It is a critical threshold in law enforcement that protects individuals from arbitrary arrest; thus, law enforcement must establish that there is a fair probability that the suspect is involved in criminal activity. Probable cause is grounded in factual circumstances that would lead a reasonable person to believe that a crime has occurred or is about to occur. This level of evidence is considered stronger than reasonable suspicion, which only requires a belief based on specific facts that a person may be involved in criminal activity, but not enough to justify an arrest. While substantial evidence and preponderance of evidence are concepts relevant in different legal contexts, such as civil cases or conviction standards, they are not applicable to the standard for making an arrest. Substantial evidence refers to a level that a reasonable person might find adequate to support a conclusion, and preponderance of evidence is the standard used in most civil cases, meaning that something is more likely true than not. Neither of these applies to the arrest context like probable cause does.