Work With Professional Investigators You Can Rely On

Welcome to Investigative Services, LLC.

We are a Private Investigations Agency dedicated to providing professional, ethical and discreet Criminal, Civil, and Marital Investigations for Individuals and Businesses.

We work with individuals, private companies, government agencies and attorneys all across the U.S in a variety of different industries throughout the world.

Using their years of investigative experience, Our team of investigators offers basic to complex investigative assistance in State or Federal criminal cases at all levels, to ensure that you get the best assistance available.

We are dedicated and compassionate about our jobs, our clients, and the law!


Frank Santin

Co-Owner & Senior Investigator

Frank Santin started his investigative background after enlisting in the US Air Force as a military policeman in January 1975. He is a Vietnam Era veteran and after 4 years of service he was honorably discharged as a Staff Sergeant.

Frank then embarked on a 24 year civilian law enforcement career with the Dover, NH Police Department reaching the rank of Lieutenant. He most notably was assigned as the Commander of the Detective Bureau and followed it with many years as a Police Prosecutor. During his tenure with the Dover Police Dept., Frank served as an instructor at the NH Police Academy for 18 yrs, specializing in the investigation of sex crimes and DWI enforcement.

As co-owner of Investigative Services, he brings to the business over 43 years of criminal investigative experience involving all major offenses. Frank provides extensive knowledge in cases involving Homicide, Sex Offenses, Drugs, and Robbery. He provides Law Firms and individuals with field investigations, analysis, and expert testimony.

Sue Smith

Co-Owner & Senior Investigator

Sue Smith began her investigative career in 1986 as an undercover operative for a major Boston based security and investigative firm. During this time, she investigated corporate theft, employee drug dealing, and many other illegal activities within a variety of New England based corporations and businesses.

She has successfully operated her own private investigative company since 1989 and earned an exceptional reputation as a thorough and professional investigator, an effective interrogator, and an advocate for women and children who are victims of abuse, sexual assault and abandonment.

As co-owner of Investigative Services, Sue brings over 33 years of experience as a multi-state investigator and expertise in undercover operations and civil/marital investigations.

Our Services

We provide over 50+ years of experience in numerous fields of investigations....

  • Criminal Investigations
  • Background Checks
  • Wrongful Death
  • Civil Cases
  • Divorce / Legal Separations
  • Marital Investigations
  • Missing Persons
  • Alive-and-Well Checks
  • Surveillance / Undercover
  • Custody Cases
  • Pre-Employment Screening
  • Asset Searches
  • Retail / Loss Prevention
  • Employee Integrity Checks

"We want to take this opportunity to thank the Investigative Services team who worked diligently in collecting, analyzing, and presenting the evidence that resulted in all State charges being appropriately and completely dropped. We remained confident and grateful that because of your team’s ability to sift through the year’s worth of details, to collect relevant statements and to quite honestly, put all the puzzle pieces of the other person’s lies together, we were successful and proving innocence.

You are all wonderful people and your competence and skill which you applied during your investigative work saved someone’s life, thank you…..thank you.

While we hope we never need your services again, we will always remember you all!

Thank you so much"

Deb & J

"Having managed the Public Defender’s Office in Rockingham County for a number of years, I had the opportunity to work with a large number of private investigators. When I opened my own office and asked other attorneys on who they use for private investigations, they highly recommended Investigative Services. I have now used the “team” that Investigative Services has put together at least a dozen times and remain pleased with the quality of work being done. I know of no other group of private investigators agency in New England that even comes close to providing the depth of knowledge and commitment to follow through that Investigative Services has been able to provide my clients."

Andrew Cotrupi, Esq.


"I have been a criminal defense lawyer for over 30 years, and have used the team at Investigative Services on many cases. Not only have I used them to interview witnesses, but they have become part of the defense team in many cases, helping to strategize and reenact events. I often utilize their services as soon as I am involved in a case, to obtain evidence that exonerates my client or creates doubt in the prosecution’s case, which has led to many clients avoiding prosecution all together. Their work has also helped me win cases at trial, and I am always able to rely on the accuracy of their work and their ability to communicate with judges and juries. I highly recommend Investigative Services LLC."

Cathy J. Green, Esq.

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