Maine licenses "professional investigators" through the State Police, Special Investigations Unit, under 32 MRS Chapter 89. The gate is a qualifying-experience ladder, a state exam, and a bond plus liability insurance — with a sponsored Investigative Assistant license as the on-ramp for newcomers.
Maine builds in an apprenticeship: the Investigative Assistant license is a sponsored, supervised on-ramp to the full credential.
Work under a sponsoring Professional Investigator as a licensed Investigative Assistant — a supervised role that, with education, becomes a qualifying path to the full license. (It's a licensed role, not a license-free job.)
Meet one of Maine's experience pathways, pass the state exam, and carry the bond and liability insurance to work on your own.
The State Police set these baseline criteria (32 MRS §8105).
Maine offers several routes to qualify — including a sponsorship-plus-education path for career-changers.
You satisfy the requirement one of several ways: completing the Investigative Assistant sponsorship program plus 60 college credits in a related field (a PI-study certificate plus 1,200 sponsorship hours also qualifies); three years as a federal investigative-service or armed-forces investigator; three years holding an equivalent out-of-state PI license; three years as a qualifying law-enforcement officer; or six years of combined work and postsecondary education.
Once licensed, you never have to retake the exam. The sponsorship-plus-education route is the realistic on-ramp for those without a law-enforcement background.
Maine's exam is administered by the State Police Special Investigations Unit — about 50 multiple-choice/true-false questions with a 76% passing score, covering professional-investigator law, concealed-carry law, and the Maine Criminal Code (Title 17-A). It's offered roughly monthly; confirm the current format with the unit.
Maine's fee structure is front-light and back-loaded; budget for the bond and insurance premiums. Confirm current figures in the Professional Investigator Handbook.
| Item | Typical | Notes |
|---|---|---|
| Professional Investigator license | $500 | $50 with the application, $450 on issuance; biennial. |
| Background check (SBI) | $21 | Criminal-record check. |
| Surety bond | $10,000 / $50,000 | Maine residents / non-residents. |
| Liability insurance | $10k / $100k / $200k | Property damage / per occurrence / aggregate. |
| State-fee total | ~$521 | Plus bond and insurance premiums. |
Bond and insurance dollar figures come from the official Professional Investigator Handbook/application — verify against the current handbook. The initial license runs two years, but subsequent renewals run on a four-year cycle. No continuing-education requirement identified.
Sponsorship + 60 credits, prior LE/federal/military experience, or the six-year combined route.
Work under a sponsoring Professional Investigator and add education.
Sit the ~50-question State Police exam (76% to pass).
Put the surety bond and the required liability coverage in place.
Complete the $21 State Bureau of Identification check.
Pay $50 with the application and $450 on issuance; renew on the 2-then-4-year cycle.
A license lets you work — it does not lift the privacy laws that bind every investigator. These are the lines that get people in trouble, license or not.
The federal Driver's Privacy Protection Act (DPPA) restricts motor-vehicle records, and recording laws govern when you can capture a conversation. Before you record anyone or pull personal data, read our recording-consent guide — it applies to a licensed investigator exactly as written.
Maine's Investigative Assistant license is the apprenticeship for those without prior investigative careers.
Use the assistant + education path. A sponsorship program plus 60 college credits (or a PI certificate plus 1,200 hours) is the route in for career-changers.
Leverage prior service. Federal, military, law-enforcement, or equivalent out-of-state PI experience can qualify you directly.
Market reality. Pay varies widely by specialty and client base — consult the U.S. Bureau of Labor Statistics for current figures rather than any single number.
The rule we never bend: no state requires an LLC to be a private investigator — not Maine, not anywhere. An LLC is liability protection, not a licensing requirement.
Maine licenses the individual investigator — there's no separate PI-agency license — so the credential is personal to you.
If you run your own practice, you may form an entity for liability protection — an LLC, a corporation, or a sole proprietorship. It's recommended, not required; no state requires an LLC to be a PI.
For the honest version of when forming one actually helps a solo operator, see our breakdown of when an LLC is worth it.
This guide is general information, not legal advice. Bond, insurance, and exam specifics live in the Professional Investigator Handbook and change — confirm current requirements with the State Police, and consult a Maine attorney for advice specific to your situation. Smoothquill points you to the real authorities; it doesn't replace them.
Maine's sponsored assistant license is the apprenticeship into the field. Start with what the work actually looks like.
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