Criminal Law and Procedure
Domain 3: Criminal Law and Procedure
This section tests offense elements, citizen arrest and detention limits, search-and-seizure boundaries, and evidence integrity. You must recognize when conduct is a crime, when you may intervene, and when your only lawful role is to observe and report.
Core rules
- Elements: most offenses require a voluntary act, a culpable mental state, causation, and a prohibited result. Larceny requires trespassory taking and carrying away of another's property with intent to permanently deprive; embezzlement involves lawful possession followed by fraudulent conversion; false pretenses involve a false statement of past or existing fact that induces reliance.
- Citizen arrest: Michigan private citizens have narrow arrest authority. The safe operational rule is that a private investigator should not detain unless a felony is being committed in your presence and immediate police assistance is unavailable. Use the least force necessary and call police immediately.
- Merchant detention: a merchant or agent may detain a suspected shoplifter briefly, in a reasonable manner, on reasonable grounds, for investigation or police response. This privilege is not a general license to interrogate or search.
- Search and seizure: private searches are not governed by the Fourth Amendment, but trespass, assault, and invasion of privacy still apply. Preserve evidence with a documented chain of custody: who collected it, when, where, and every transfer.
Worked example
A retail client reports an employee taking cash. You review register logs, interview the employee in a non-custodial setting, and recover a deposit bag from a desk. Do not block the door or demand a confession. Document the bag's location and condition, photograph it before moving it, and hand it to police with a signed receipt.
Traps
Believing a citizen's arrest is risk-free. Searching a person or bag without consent or lawful authority. Breaking chain of custody by leaving evidence in an unsecured desk.