Investigative Principles, Techniques, and Case Planning
Start with the decision, not the technique
Every investigation exists to support a decision - a hiring decision, a claim, a lawsuit, a custody arrangement, a missing-person recovery. Case planning begins with intake: identify the client and who is authorized to give instructions, restate the objective in one sentence, and separate what is known from what is unknown. Then ask what facts would change the answer. Those become your investigative priorities.
Build the plan
A workable plan contains: (1) objective and deliverable; (2) known facts and sources already checked; (3) hypotheses - at least two, including the innocent explanation; (4) a source-and-method matrix matching each unknown to a lawful technique (public records, database queries made for a permissible purpose, lawful records requests, interviews, canvass, surveillance, site examination); (5) written legal and ethical limits; (6) sequence, schedule, budget, and client checkpoints; (7) a documentation and retention plan.
Traps
- Mission creep: the client adds targets or goals mid-case without amending scope, budget, or authority.
- Unachievable promises: guaranteeing a result, such as promising proof of an affair within a week.
- Unlawful objective: instructions to enter a home, access a phone, or obtain records by pretext.
- Single-hypothesis thinking: confirmation bias turns the first theory into the only theory while contrary facts are ignored.
- No negative documentation: the file records hits but not the checks that came back empty, so it cannot show diligence.
Worked example: A client says, find out if my ex is working while collecting benefits. Restated objective: document employment and work activity of a named subject during a defined period. Unknowns: employer, schedule, worksite. Methods: public and licensed database queries, observation from public vantage points, lawful records requests. Written limit: no entry onto private property and no pretext calls to the employer. Deliverable: a dated report with a time-stamped observation log and any documentary evidence.