What a Private Investigator Actually Does

A private investigator is a person licensed by your state to conduct investigations for individuals, businesses, and attorneys. They are not police officers and have no special legal powers — they gather information using interviews, public records, surveillance, and background checks. What they can do depends entirely on state law, which varies widely. Some states allow investigators to conduct surveillance; others restrict it sharply. Some allow undercover work; others ban it outright.

Most private investigators work on cases involving infidelity, child custody disputes, missing persons, background checks for employment or business partnerships, fraud investigations, and asset location. They bill by the hour, by the day, or by the project. Costs range from a few hundred dollars for a straightforward background check to several thousand for a multi-week surveillance operation. You pay upfront or on a retainer basis — money held in trust that the investigator draws from as work progresses.

Key Takeaways

  • Private investigators must be licensed by your state, and licensing requirements, permitted activities, and hourly rates vary significantly by location.
  • You will need to sign a contract that specifies what the investigator will do, how much it costs, and what information they will deliver to you.
  • Investigators cannot break laws to gather information — they cannot trespass, hack accounts, impersonate police, or wiretap — and hiring one to do so makes you liable.
  • The information an investigator gathers may or may not be admissible in court, depending on how it was obtained and what kind of case you are in.
  • If you are involved in a legal dispute, your attorney should vet any investigator you hire and may have preferred investigators they work with regularly.

How to Find and Vet a Licensed Investigator

Start by confirming that any investigator you consider is actually licensed. Each state maintains a licensing board or agency — often the state police, the attorney general's office, or a dedicated licensing board. Search your state's name plus "private investigator license" to find the right office, then search their database by name or license number. If an investigator cannot give you a license number or their name does not appear in the state database, do not hire them.

Ask for references from previous clients and contact them directly. Ask whether the investigator delivered what was promised, whether the work stayed within budget, and whether the information was useful. If the investigator is working on a legal case, ask your attorney for a referral — many attorneys have relationships with investigators they trust and know will produce work that holds up in court. Check online reviews on Google and the Better Business Bureau, but treat them as one data point, not the whole picture.

Interview at least two investigators before hiring. Ask what they specialize in, what your state allows them to do, how they charge, and what they need from you to start. A good investigator will ask you detailed questions about what you need and why, will explain what they can and cannot legally do, and will give you a written estimate before beginning work.

What to Expect in a Contract and Scope of Work

Before an investigator begins work, you should receive a written contract. This contract should state exactly what the investigator will do, how much it will cost, how they bill (hourly, daily, or flat fee), and what you will receive at the end. It should also state the investigator's license number and the state that issued it. Read this carefully — a vague contract that says "investigate the matter" without specifics is a red flag.

The contract should also include limits on what the investigator will do. For example, it might say they will not conduct surveillance after 10 p.m., or that they will not contact your ex-spouse directly, or that they will stop work if costs exceed a certain amount. These limits protect you and the investigator. Ask the investigator to explain anything you do not understand before you sign.

Understand that the investigator works for you, not for the court or for justice in general. They are gathering information you have requested. If that information turns out to be unhelpful or even harmful to your case, you still pay them. Discuss with your attorney beforehand what information would actually be useful and what would not, so you do not pay for work that does not matter.

What Investigators Can and Cannot Do Legally

Private investigators operate under state law, and the rules are strict. They cannot trespass on private property, hack into email or social media accounts, impersonate police or government officials, record phone calls without consent (in most states), or wiretap anyone. They cannot bribe public officials or access sealed court records. They cannot follow someone into a bathroom or bedroom, and they cannot photograph someone through a window into a private space. If an investigator does any of these things, they have broken the law, and you may be liable for hiring them to do so.

What they can do varies by state. Many states allow surveillance in public places — parking lots, streets, restaurants. Some allow investigators to pose as someone else in online communications. Some allow them to access public records databases that are not available to the general public. Some allow them to interview witnesses without identifying themselves as an investigator. Your state's licensing board publishes rules about what is permitted; ask the investigator to show you the relevant section of your state's law before you hire them.

If you ask an investigator to do something illegal, they should refuse. If they agree, that is a sign they are not trustworthy and not properly licensed. Do not hire them.

How Investigator Reports Are Used in Court

Information gathered by a private investigator may or may not be admissible in court. That depends on how it was obtained and what kind of case you are in. In a criminal case, evidence obtained illegally is inadmissible and can get your attorney in trouble. In a civil case (like divorce or business disputes), the rules are somewhat looser, but evidence obtained through illegal means is still usually excluded.

Even if the information was obtained legally, a judge may decide it is not relevant to the case or that it is unreliable. For example, a photograph taken by an investigator might be admissible, but testimony from the investigator about what they saw might not be, depending on the rules of evidence in your state and the type of case.

This is why it is critical to work with your attorney before you hire an investigator. Your attorney can tell you what kind of evidence would actually help your case, how it needs to be gathered to be admissible, and whether the cost is worth it. Some cases are won on investigator reports; many are not.

Costs and How Investigators Bill

Private investigator rates vary widely by state, by city, and by the investigator's experience. In rural areas, you might pay $35 to $50 per hour. In major cities, rates often run $75 to $150 per hour or more. Surveillance work is usually billed by the day and costs more than office work like background checks or public records research. A straightforward background check might cost $200 to $500. A week of surveillance could cost $2,000 to $5,000 or more.

Most investigators require a retainer — an upfront payment, usually $500 to $2,500, that they draw from as they work. When the retainer runs out, they ask for another one. Some investigators offer flat-fee packages for common work like background checks. Always get a written estimate before you agree to anything, and ask what happens if the work takes longer than expected or if you want to stop early.

Keep in mind that investigator costs add up quickly. Before you hire one, talk to your attorney about whether the information you need is worth the money. In some cases, the answer is yes. In others, the information is not going to change the outcome, and you would be better off spending the money elsewhere.

Red Flags and How to Avoid Scams

Be wary of investigators who may provide results, promise to "find anything," or claim they can access information that is not publicly available. No legitimate investigator can may provide they will find what you are looking for. Be wary of anyone who asks for payment in cash only, who does not provide a written contract, or who refuses to give you their license number. Be wary of investigators who pressure you to hire them quickly or who claim they have a "limited window" to do the work.

Do not hire an investigator who suggests doing anything illegal, even if they frame it as "just this once" or "nobody will know." That is how people end up in legal trouble. Do not hire an investigator who will not explain what they are doing or how they are doing it. You have a right to know what you are paying for.

If you are working with an attorney, let them vet the investigator. Attorneys know which investigators are reputable and which ones cut corners or produce unreliable work. If you are not working with an attorney, spend extra time checking references and confirming licensing before you hire anyone.

Frequently Asked Questions

Can a private investigator follow someone without their knowledge?

In most states, yes, as long as the investigator stays in public places and does not trespass or break other laws. However, some states have restrictions on surveillance, and some require the investigator to disclose their identity under certain circumstances. Ask your investigator what your state allows before you hire them.

Will information from a private investigator hold up in court?

Maybe. It depends on how the information was gathered, what kind of case you are in, and what the judge decides. Work with your attorney before you hire an investigator so they can tell you what kind of evidence would actually be useful in your case.

What if I hire an investigator and they break the law?

You could be held liable for their actions, even if you did not know they were breaking the law. This is why it is critical to hire a licensed, reputable investigator and to make clear in your contract what they can and cannot do.

How long does a private investigation usually take?

It depends entirely on what you are asking the investigator to do. A background check might take a few days. Surveillance could take weeks or months. Ask the investigator for a timeline estimate before you hire them.

Can I hire a private investigator if I do not have an attorney?

Yes, but it is riskier. Without an attorney to guide you, you might hire an investigator to gather information that is not useful, not admissible in court, or obtained illegally. If you are involved in a legal dispute, consider consulting an attorney before you hire an investigator.