Most licensed private investigators in New Hampshire and Massachusetts bill by the hour against a retainer, and a typical case ends up costing somewhere between a few hundred and a few thousand dollars. Surveillance-based cases — infidelity, workers’ comp, custody — commonly run $800 to $3,000 depending on how many hours of fieldwork the case needs. A straightforward background check or people locate is usually far less. Below is exactly what drives the number, so you can budget before you call anyone.
How Private Investigators Charge
There are three pricing models you’ll run into in NH and MA. Reputable firms will tell you up front which one applies to your case.
- Hourly rate + retainer. The most common model for surveillance and investigative work. You pay a retainer (a deposit) and the investigator bills hours against it — fieldwork, travel, report writing. Unused retainer is typically returned or credited.
- Flat fee. Used for defined, predictable tasks: a background check, a records search, serving legal papers, locating a person.
- Daily or project rate. Sometimes quoted for multi-day surveillance or complex corporate cases with a clear scope.
Expenses — mileage, tolls, database fees, court record costs — are usually billed separately. Ask whether they’re included in the quote.
Typical Costs by Type of Case
Cheating spouse / infidelity surveillance
Almost always hourly. Most cases take two to four surveillance sessions over one to three weeks, and the majority resolve in the $800–$2,500 range. The biggest variable is how predictable the subject’s routine is — a clear pattern means fewer hours. More on how infidelity investigations work.
Child custody investigations
Hourly, often spanning several custodial periods to establish a pattern rather than a single moment. Most custody cases run $1,000–$3,000. Reports are formatted for NH Family Division or MA Probate & Family Court, which adds documentation time but is what makes the evidence usable. What a custody investigation documents.
Workers’ comp and insurance surveillance
Usually quoted as blocks of surveillance hours or days to insurers, employers, and defense counsel. Cost scales with the number of observation days needed to document activity. Surveillance services for insurers and attorneys.
Background checks and locating people
Typically flat-fee or a small number of hours. A professional background investigation costs more than a $30 online report because it uses primary sources — actual court records, verified employment, reference interviews — but it’s generally the least expensive category of investigative work. Background checks and skip tracing.
What Makes a Case Cost More (or Less)
- Hours of fieldwork. The single biggest driver. Surveillance is billed by the hour, including waiting.
- Predictability of the subject. A known schedule means targeted sessions; an erratic one means more time.
- Geography. Cases that cross the NH/MA line are efficient with a dual-licensed investigator and expensive when two firms have to be involved. Where we work.
- Number of investigators. Mobile surveillance sometimes needs two vehicles to avoid detection.
- Court-ready documentation. Timestamped video, chain of custody, and a written report take time — but they’re the entire point if the matter goes before a judge.
- Testimony. Deposition or trial appearances are billed separately.
How to Keep the Cost Down
Come to the first conversation with what you already know: the subject’s schedule, vehicle, usual locations, and the specific question you need answered. The more precise the question, the fewer hours it takes to answer. A good investigator will also tell you honestly when surveillance is unlikely to get you what you need — that conversation should be free.
How We Price Cases
At Donahue Investigative Services we bill hourly against a retainer, quote the expected range before you commit, and debrief you after every session so you decide whether to continue. We don’t pad hours — if a case resolves quickly, you pay for what was done. The initial consultation is free and confidential: 603-785-2800.
Frequently Asked Questions
What is the hourly rate for a private investigator in NH or MA?
Rates vary by firm and case type. Licensed, experienced investigators in New Hampshire and Massachusetts generally bill somewhere in the range of roughly $75 to $150 per hour, with specialized or multi-investigator work costing more. Always ask what the hourly rate includes and what’s billed as an expense.
Do I have to pay a retainer up front?
For hourly cases, usually yes. A retainer is a deposit the investigator bills against. It protects both sides: you know the maximum exposure, and the investigator can begin fieldwork immediately. Ask whether unused retainer is refunded or credited.
Is a private investigator worth the cost for a divorce case?
When the outcome hinges on proving something — infidelity affecting alimony, cohabitation, or a parent’s conduct in a custody dispute — documented evidence can be the difference in the result. The cost of an investigation is often small relative to what’s at stake in the settlement. Your attorney can tell you whether evidence would actually move your case.
Why not just use a cheap online background check?
Online services pull from aggregated databases that are often incomplete or out of date, and they can’t be used for employment decisions without FCRA compliance. A licensed investigator verifies against primary sources. For a high-stakes hire, tenant, or business partner, the accuracy difference is the whole point.
Donahue Investigative Services & Executive Protection — Salem, NH. Licensed in New Hampshire (#M-2025-0424) and Massachusetts (#LP1599A). Former law enforcement, 56+ combined years.
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