How does a private investigator conduct surveillance?

A licensed PI conducts surveillance by observing a subject from a lawful vantage point — typically a vehicle in a public area — and documenting their activities, movements, associations, and behavior using video and photography. The investigator maintains a written log with timestamps and GPS-confirmed observation points. All documentation is maintained in a chain of custody for potential court use.

How do I start a surveillance investigation?

Contact a licensed PI firm for a confidential consultation. You'll discuss the situation, the objective, available subject information, and the timeframe. The firm will scope the investigation, provide a cost estimate, and require a retainer before deployment begins. Thor Secure typically responds within hours and can deploy within 24-72 hours of engagement.

What information do I need to give a private investigator?

The more the investigator knows, the more efficiently they can work. Useful information includes the subject's full name, a recent photograph, known vehicle description and license plate, home and work addresses, known routine or schedule, and any recent changes in behavior. You do not need all of this to start — the investigator can work with whatever you have.

What do I receive at the end of a surveillance investigation?

At the conclusion of a surveillance engagement, you typically receive a written investigative report with a timeline of all observations, timestamps, and GPS-confirmed locations; video footage with date/time metadata; and still photographs where relevant. Evidence is provided in formats suitable for personal review, attorney use, or court submission.

How Surveillance Investigations Work | Licensed PA PI

Q: Will the subject know they are being investigated?

A professional surveillance investigator conducts all operations covertly. The subject should never be aware of the surveillance. Professional investigators use unmarked vehicles, plain clothing, and established counter-surveillance techniques to remain undetected. Compromising the surveillance — making the subject aware they are being watched — is one of the most serious errors an investigator can make.

The Full Process

Confidential Consultation

Every investigation begins with a confidential conversation. You describe the situation — who, what, where, why — and the investigator listens, asks clarifying questions, and assesses what the investigation would require. At Thor Secure, this consultation is free. We'll tell you honestly whether surveillance is the right tool for your situation, or whether a different investigative approach would be more effective.

Case Scoping & Estimate

After the consultation, we scope the investigation — how many days of surveillance, what hours, what geographic area, and what specific objective we're documenting. We provide a written estimate before any work begins. Surveillance cases are typically billed on a day-rate or hourly basis with a retainer. You'll know exactly what you're paying before the first investigator deploys.

Subject Research & Pre-Surveillance Preparation

Before going in the field, the investigator reviews all available information on the subject — known addresses, vehicle information, routine patterns, workplace location, social media presence. The more background available, the more efficiently the field time is used. Investigators may also conduct a pre-surveillance drive of key locations to identify observation positions.

Field Surveillance

The investigator establishes a covert observation position — typically in an unmarked vehicle in a public area near the subject's known residence, workplace, or other target location. The investigator documents everything they observe: arrivals and departures, persons contacted, locations visited, activities conducted. All observations are recorded with timestamps and GPS coordinates. Video footage is captured continuously during active observation.

Professional investigators do not engage with the subject, follow subjects onto private property, or take any action that could reveal their presence. A burned surveillance — one the subject becomes aware of — produces no usable evidence and may alert the subject to alter their behavior.

Mobile Surveillance

When a subject is mobile — leaving their home or workplace — the investigator follows. Mobile surveillance in Greater Philadelphia requires knowledge of the local road network, the ability to maintain surveillance across multiple vehicles and intersections, and judgment about when to fall back to avoid detection. Our investigators have backgrounds in law enforcement surveillance operations — mobile surveillance is a trained skill, not improvisation.

Daily Reporting

At the end of each surveillance day, you receive a written activity report covering the day's observations — timeline, locations, persons observed, and any significant activity. If the day produced no significant findings, you receive that too. We do not pad reports or create false activity to justify continued billing.

Evidence Compilation & Final Report

At the conclusion of the engagement, you receive a comprehensive final report and all footage. The report includes a complete timeline of all observations across all surveillance days, GPS-confirmed observation locations, photographs and video footage with date/time metadata embedded, and a summary of findings relative to the case objective.

All documentation is prepared with court admissibility in mind. If your case may involve legal proceedings, we provide materials in formats your attorney can use directly.

What You Need to Provide

The more information you can provide, the more efficiently we can work. Useful subject information includes:

Full legal name
Recent photograph
Known vehicle(s) — make, model, color, license plate
Home address and/or workplace address
Known schedule or routine
Any recent behavioral changes worth noting

You do not need all of this to start. We can work with partial information — though gaps increase the number of field hours required to locate and document the subject.

What Surveillance Can and Cannot Establish

Surveillance is highly effective at documenting what a person does in observable contexts. It can document who they meet, where they go, when they come and go, and their physical condition and activity level. It cannot document private conversations, activities inside buildings, or anything that occurs outside the investigator's line of sight.

For matters where documentary or digital evidence is the primary need — financial records, online activity, communications history — surveillance may need to be combined with other investigative techniques. We'll tell you which approach is right for your specific objective during the consultation.

Frequently Asked Questions

Will the subject know they are being investigated?

No. Professional surveillance investigators operate covertly using unmarked vehicles, plain clothing, and established counter-surveillance techniques. Compromising the surveillance is one of the most serious errors an investigator can make — and it prevents you from getting the evidence you need. Our investigators come from law enforcement backgrounds where surveillance discipline was a professional standard.

How many days does a surveillance investigation take?

It depends on the objective. A targeted activity check — confirming or clearing a specific suspicion — may require one to three days. Ongoing documentation for custody proceedings or fraud investigation may run several weeks. We scope every case individually and give you a realistic timeline before work begins.

What if the investigation finds nothing?

We document what we observe — including the absence of activity. If a surveillance engagement produces no significant findings relative to your case objective, that result is reported honestly. We do not create or embellish findings. A negative result is still a result — one that may give you the answer you needed.

Can surveillance evidence be used in divorce court?

Lawfully obtained PI surveillance evidence is generally admissible in Pennsylvania civil proceedings, including divorce and custody matters. Evidence must be gathered using legal methods and maintained with proper chain of custody. Evidence gathered through illegal means — trespassing, unauthorized audio recording — is inadmissible. We gather evidence with admissibility standards in mind from the start. See our full guide: What a PA Private Investigator Can Legally Do.