Cullen Investigations
A Full Service Investigation & Consulting Firm




Providing Trial Assistance to Attorneys and Law Firms. Specializing in Criminal Defense, Appeals/Post-Conviction Relief, Comprehensive Background Investigations, Due Diligence, Legal Investigation Services AND MORE.

Legal Investigation Services

Legal investigations are primarily concerned with investigating a dispute between individuals regarding their civil and legal rights. The purpose of the investigation is to gather the necessary evidence for trial. To guarantee success in your civil trial, it is recommended to seek assistance from a professional private investigator. At Cullen Investigations, protecting rights is of the utmost importance to us, and thus we perform a myriad of civil investigations to safeguard you, your family and/or your business from any form of unethical activity. 

Our Attorney's and Legal Investigative Services Include:

  • DUE DILIGENCE INVESTIGATIONS – Our due diligence investigation services are designed to assess the background and reputation of a potential business partner(s) or key player(s) in a venture before entering into a substantial financial relationship. We assist venture capital firms, private equity firms, investment banks, wealthy individual investors and financial institutions understand the risks before entering into a joint venture, merger, acquisition or a significant financial or investment transaction. We utilize ethical and lawful information-gathering methods, using technological sources, open-sources, proprietary databases and information ascertained through human intelligence to develop information on the reputations of individuals to protect our client’s interests.
  • CIVIL LITIGATION INVESTIGATIONS – Whether it be a crossing accident/fatality or a railroad employee is injured or killed while on duty, Cullen & Associates can help. Eric Cullen worked for Union Pacific Railroad for over six years before opening Cullen & Associates and knows the railroad inside and out from the various unions that support the laborers to railroad management. We will work closely with your counsel to insure that you get the best evidence available to your 
  • LOCATION SERVICES  – Cullen Investigations, LLC provides services to a range of clients in locating missing heirs and beneficiaries. We find needles in a haystack. Our team depends on our document research expertise, proficiency with global logistics, and our unparalleled investigative skills to conduct investigations in connection with:
    • Estate & trust settlement matters
    • Distribution of unclaimed assets
    • Suits to quiet title to real property
    • Establishment of ownership of oil, gas, and mineral rights or other legal interests.
  • APPEALS & POST CONVICTION RELIEF DIVISION – Hiring Cullen & Associates to investigate your case could provide you with the newly discovered evidence that is necessary to overturn your conviction. Many individuals seeking to have their convictions overturned need the services of a competent investigation agency even more than they need the services of an attorney. Cullen & Associates will investigate your case and deliver the information needed to make an informed decision on whether or not to hire an attorney. If counsel is needed during or following our investigation, we can assist you in finding a reliable and experienced attorney.
  • PROCESS SERVICE –Cullen Investigations has a 99% successful service rate. We serve and have served every type of legal document imaginable. We currently service over 30 attorneys in the Tulsa area. We can locate anyone and serve your papers on a standard or rush basis. We have a virtual “arsenal” of tactics to effect service on the most difficult to serve individual. We serve summons and complains, subpoenas, restraining orders and all other types of court documents. We also provide delivery service for letters, legal documents and other types of legal communication. We have15+ years of experience in serving difficult legal process and have a proven track record and the experienced office staff to respond to your special needs. If you need to locate a witness or defendant in order to make service, we can do it. We have reasonable and competitive pricing and look forward to being able to assist you in Oklahoma.

    We have a network of professional process servers for service of process both nationally and internationally. We are licensed private investigators and are fully insured.


From our headquarters in Tulsa, Oklahoma, business decision makers and high net worth individuals rely on Cullen Investigations background check services to provide an in-depth look at individuals relating to pre-employment investigations, executive background checks, or board of director appointment. Our comprehensive background investigation analysis and detailed report gives you simple, focused information and intelligence that helps clients make more informed decisions.

We utilize ethical and lawful information-gathering methods, using technological sources, open-sources, proprietary databases and information ascertained through human intelligence to develop information on the reputations of individuals to protect our client’s interests.


Adultery brings fear, denial, and financial ruin. Any form of adultery puts your life on hold and your finances at risk. Whether your partner is starting to wander off or involved in a full-blown affair, you need to know and know immediately so that you can make choices that are right for you.

Divorce and child custody cases can benefit from the use of experienced private investigators. Cullen Investigations has been successful in obtaining documentation regarding adultery, child custody, lifestyle, assets, income, roommates, friends and parents, including their criminal history, work history, assets, locating and interviewing witnesses, and obtaining information regarding cheating, adultery, abuse or neglect in hundreds of cases. We Can Provide You With The Information You Need.

  • We are licensed by the State ofOklahoma and have been providing investigative services in divorce and child custody cases for the past ten years.
  • We have the experienced private investigator staff, knowledge of the law and surveillance equipment necessary to properly prepare you and your attorney with the necessary and factual evidence to win your case.

In every family law case, whether divorce or child custody/visitation case, there are issues of both law and fact. Our expertise can help make the facts become clearer. Solid, verifiable facts can affect the outcome of your case. Even the best attorney in the world wants facts on their side.

Stop ‘wondering” if your significant other is with someone else by simply picking up the phone and calling us right now to speak with an experienced private investigator. We will keep your inquiry completely confidential and provide you with our recommendations on how best to assist you.

Asset Searches

Whether needing asset searches on individuals or corporations, one thing is constant: there is always a way to trace the history of money. Domestic Asset Searches and Lifestyle Assessments are needed if you suspect that your spouse is channeling money away from the family accounts or planning a divorce. Then you definitely should consider a professional asset search if things start to “get ugly”. These types of asset searches are also common when entering into a prenuptial condition or simply to find out the truth about the financial claims of an individual.


Child Custody litigation is emotionally exhausting and needs to be handled with the utmost discretion and accuracy. Cullen & Associates has assisted in over 100+ child custody cases and has become reputable among clients and attorneys for being effective and knowledgeable in this area. Cullen & Associates uses a wide range of options to help acquire the information needed in litigation.