Investigative Principles and Practices
Investigative Principles and Practices
This domain tests whether you can run a lawful, client-focused investigation from intake to closure: defining scope, selecting the least intrusive method that answers the question, planning surveillance and interviews, and preserving what you learn. Missouri does not issue a state PI license, so your authority comes from the client's written engagement and general law, not a badge.
Core rules
- Start with a written scope: who, what, why, deadline, budget, and what the client will do with the result.
- Choose proportionate methods; a records review may answer a question that does not justify surveillance.
- Plan surveillance: legal vantage point, vehicle and plate concealment, relief, emergency contact, and a log recording times, locations, and observations.
- Interview in a planned sequence: background, open-ended account, timeline, clarifying questions, and a signed statement if appropriate. Avoid leading questions.
- Record facts contemporaneously and separate observation from inference.
Worked example
A workers' compensation client reports a subject is mowing his lawn despite a claimed back injury. You confirm the address, check local ordinances, park on a public street, and record from a lawful vantage point. You log arrival and departure times and describe actions ('pushed a walk-behind mower for 22 minutes'), not conclusions ('clearly faking'). Reasoning: public observation from a lawful place is defensible; entering the yard or using a ladder over a fence is trespass. The report ties each claim to time-stamped media.
Traps that cost marks
- No written scope, leading to scope creep and disputed billing.
- Confirmation bias: recording only activity that supports the client's theory.
- Trespass or peering into windows, which can poison the case.
- Leading interview questions and paraphrasing quotes.