WALI Best Practices for Private Investigators



  • New Clients: If first contact is by phone or meeting, verbally set all expectations regarding work to be completed, investigator and client responsibilities, timelines, payment schedule and fees for any additional work. Follow up with a retainer agreement, detailed contract or Statement of Work (SOW), outlining all of these areas discussed prior to performing the actual work. 
  • After determining scope of work and compensation, provide an Assignment Sheet or Investigative Plan to the Client which outlines, as best as possible, timelines and stages involved in the investigation with fees, if applicable, to coincide with work to be completed.
  • For Established Clients: Maintain consistent business practices and payment schedules. Apply contract or SOW to each assignment if that is your agreement with an established client.
  • When submitting your Invoice, consider attaching a copy of your W-9 form the first time. This will generally expedite payment, especially when billing a medium-to-large company.
  • If applicable to the agreement with the Client, the Invoice should contain all pertinent information, such as dates and hours worked, task and total charge for that period. Be concise and only include information useful for the Client to understand the service performed.


  • Prepare a complete, as feasible, pre-execution plan. The plan should include, as applicable, all computer checks necessary prior to deployment (criminal, civil, social media, location, background information and history, etc.).
  • Identify all the basics (who, what, where, when, why and how) as best as possible prior to beginning the actual investigation.
  • Gather as much information, no matter how insignificant if might seem at first, as possible. The process of eliminating non-pertinent information from the valuable data is the key to conducting a successful investigation.


  • Prior to beginning the person locate, advise the Client that as a standard procedure, the first task in this process will be to confirm the Client’s identity, address, contact information and that you will be conducting court checks for outstanding no-contact orders, or similar past or current restraining orders, especially as it involves the subject of the person locate assignment.
  • At the onset of the person locate, give the Client the opportunity to provide you with any written material, or similar media, to provide to the subject once you have located him/her.
  • Advise the Client that, due to liability and privacy issues, you will agree to conduct the person locate with the understanding that once the subject is located you will notify the subject that the Client wishes to make contact with him/her. Provide the subject with the Client’s contact information and also advise him/her that you have not divulged their whereabouts, or any other information, to the Client at this time.
  • In the event the Client has a retained the services of an attorney, verify the relationship is legitimate and offer the option to the Client to provide the personal locate information findings directly to the attorney.


  • The Surveillance plan should include, as feasible, all computer checks necessary prior to deployment (maps, police information, patterns and background/history of the subject and location).
  • Prepare a list of equipment required for conducting the surveillance. Anticipate items from prior research and past experiences, if helpful. General considerations include; vehicle type and other means of transportation, type and variety of clothing, camera/video, logs, radios, food and snacks, creature comforts, etc.
  • Ensure all surveillance equipment is in proper working order. Test all to be certain.
  • If feasible (and part of the Client’s payment agreement), conduct a “dry run” of the area where the surveillance will be conducted. Become familiar with all normal activities of the location (traffic and pedestrian flows, public transportation schedules, store hours, best places to make observations, etc.).
  • If not intrusive, use small recorder or similar to enter your observations, actions observed, and other pertinent surveillance data for later inclusion in your activity report.


  • Prepare detailed notes and strategy regarding how each interview will be conducted.
  • Prepare as many questions as you can before the interview; keeping in mind that spontaneous follow up questions usually make for the best types of interviews when you require more specific information.
  • Determine best location to conduct interviews (your office, attorney’s office, client’s office, public location, subject’s location, etc.).
  • Location choice of where to conduct interview may be dependent upon the “type” of person being interviewed (i.e., suspect, witness, complainant).
  • Generally, live interviews are more productive than phone interviews.
  • In most every investigation, it is necessary to get a documented statement from the person being interviewed. The best form is the individual’s handwritten statement. In absence of that, a word document that is signed is permissible. Less desirable, but acceptable, is a voice recorded statement. (WARNING – Before using a recording device, be familiar with laws regarding voice interception. Washington State is a “two party” state, which means the permission of both parties must be had before a consent recording is made. If using a recording device, ensure you have the other person’s permission to record the interview at the beginning of the recording). 


  • Reports should always follow a simple and concise format that includes the Cover Page with all pertinent information (Investigator’s name and contact information, Subject’s name, Client’s Name, Case Number, and Date of Report).
  • The body of the Report should include the following sections; Assignment, Background Information, Investigation Results (including, if applicable, interviews, surveillance, forensic results), Conclusion, Opinion and Recommendations (only if requested during the initial agreement with Client).
  • If utilizing a sub-contractor for all or part of the assignment, include a copy of his/her license and insurance coverage with the final report.


  • Recommend you retain your case files for seven years before destroying them.
  • Keep all hardcopy documents in the file and backup all softcopy data. Note the existence of softcopy information in your case folder with its location.
  • Depending on attorney instructions, retain or destroy your written notes.
  • Maintain all notes pursuant to Client conversations, written agreements, contracts and invoices.


  • Ensure the sub-contractor possesses the expertise you are seeking.
  • Obtain copies of all licenses and related policies and ensure they are current. These documents include a private investigator’s license, business license and insurance policy (specifying type and amount of coverage).
  • Have the sub-contractor sign a non-disclosure agreement and provide a current W-9 form prior to working on the assignment.
  • If you are not directly familiar with the sub-contractor, ask trusted colleagues and also query professional complaint boards, business groups, etc.
  • Conduct a thorough interview of the sub-contractor if you are not familiar with his/her background and experience.
  • If time and finances permit, have the sub-contractor participate in a mock exercise specific to the task you are seeking him/her to perform.


  • Washington State courts have determined that placing a GPS-type tracking device to an individual’s vehicle is extremely intrusive and also a 4th Amendment violation. Therefore, legal installation and use of these type devices can only occur after establishing probable cause, and then obtaining a court order/warrant authorized by a judge.
  • A private investigator should fully understand existing local, state and federal laws before considering this method of surveillance.
  • It is strongly advised that the private investigator consult with an attorney prior to installing a consent tracking device. Scenarios surrounding actual occupant(s) and/or drivers must be thoroughly researched and considered before deploying a device, even with consent given.