Donahue Investigative Services & Executive Protection
Licensed, bonded, confidential and discreet
Donahue Investigative Services & Executive Protection
Licensed, bonded, confidential and discreet
About Donahue Investigations
Our Mission
At Donahue Investigations, our mission is to provide comprehensive and reliable private investigation and executive protection services. We are committed to uncovering the truth for our clients while maintaining the highest standards of safety, professionalism and confidentiality.
Licensed and bonded in New Hampshire (# M-2025-0424) and Massachusetts (# LP1599A)
What We Do
Donahue Investigative Services LLC, is a private investigation and executive protection firm, providing a full spectrum of services including:
- Civil & Criminal Investigations
- Corporate & Legal Investigations
- Executive & VIP Protection
- Surveillance & Covert Operations
- Insurance Fraud & Background Checks
- Cyber Investigations & Online Threat Mitigation
- Courtroom Testimony & Legal Support
Who We Are
Mark J. Donahue, Investigations and Executive Protection
Mark J. Donahue is a highly respected investigator and security professional with over three decades of experience in law enforcement, private investigations, and executive protection. As President of Donahue Investigative Services LLC, he has built a reputation for professionalism, integrity, and results-driven investigative work across New England and beyond.
Mark’s investigative career spans 34 years, including 19 years of distinguished service with the Salem, New Hampshire Police Department, where he managed major criminal investigations, such as homicide, narcotics trafficking, and white-collar crimes. His expertise extended into federal task force operations, serving with the DEA Drug Task Force, the Internet Crimes Against Children (ICAC) unit, and the Attorney General’s Gang Task Force. Mark also served as a SWAT Crisis Negotiator, where he became known for his calm, measured approach to high-stakes incidents.
Mark continued his law enforcement career when he signed on with the Harvard University Police Department, serving as Patrol Supervisor; supervising, assisting and managing the afternoon patrol shift. Mark quickly moved on to Detective Seargeant, overseeing sensitive internal investigations and managing strategic operations within the
Detective Bureau as well as serving in the Dignitary Protection Unit
organizing and executing Operational Plans for dignitaries visiting the Harvard University Campus. Mark also filled the role of Administrative Sgt, where he held many responsibilities which included management of the fleet vehicles as well as a renovation of the Police Department.
Before his law enforcement tenure, Mark was employed as an investigator at McCain Investigative Services in Boston, MA, where he ultimately became a manager with a client base exceeding 1,100 corporate and private entities. The firm handled corporate espionage, insurance fraud, and civil litigation support for Fortune 500 companies that laid the foundation for their current success.
Known for handling some of the largest civil lawsuits in New England history, Mark has investigated major cases involving Big Pharma, Superfund waste sites, the tobacco industry, and financial and food supply corporations. His clients value his discretion, ethical standards, and unwavering dedication to uncovering the truth.
A licensed and bonded private investigator, Mark is also a former federal task force agent, FBI-certified crisis negotiator, and holds multiple law enforcement and protective certifications. His background with the U.S. Coast Guard and multiple police academies across New England further underscore his commitment to service and public safety.
At Donahue Investigative Services LLC, Mark and his team have provided a full spectrum of services including:
- Civil & Criminal Investigations
- Corporate & Legal Investigations
- Executive & VIP Protection
- Surveillance & Covert Operations
- Insurance Fraud & Background Checks
- Cyber Investigations & Online Threat Mitigation
- Courtroom Testimony & Legal Support
Today, Mark continues to lead with professionalism, experience, and trust—offering investigative excellence to clients who demand nothing less.
Joseph E. McCain, Investigations and Executive Protection
Joseph E. McCain is a seasoned public servant and investigator whose career spans more than three decades in law enforcement, child protection, and investigative services. Formerly serving as a Child Protective Service Investigator III for the State of New Hampshire’s Department of Health and Human Services, Joseph brings extensive expertise in assessing child welfare cases, conducting sensitive interviews, and developing intervention strategies to safeguard vulnerable children. His work involves court testimony, risk evaluations, and family counseling to ensure the well-being and stability of children across the state.
Before joining DHHS, Joseph built a distinguished career in law enforcement with the City of Somerville Police Department, where he rose through the ranks to become a Lieutenant. Over his 26-year tenure, he led patrol operations, supervised detectives, managed investigations, and coordinated community engagement programs such as the YMCA’s “Cops and Kids” and “Adopt-a-School” initiatives. His valor and leadership were recognized with numerous honors, including the George L. Hanna Memorial Medal of Honor for Bravery, Medals of Valor, and multiple commendations from both civic and law enforcement organizations. His service was also featured in The Boston Globe and The Improper Bostonian for his exceptional dedication and heroism.
Beyond policing, Joseph joined his dad at McCain Investigative Services in Boston MA, a licensed private detective agency providing investigative, surveillance, and protective services to major corporate clients in , the tobacco, pharmaceutical, financial and food supply industries. His leadership combined discretion, professionalism, and integrity, earning trust from both private and corporate sectors.
His dedication to protecting children extends to his work as a Juvenile Courts Investigator for Essex and Middlesex Counties and as a Guardian Ad Litem/Educational Surrogate, where he advocates for children’s educational rights and welfare in judicial settings. Previously, as Program Director at Alliance House in Danvers, Massachusetts, he developed therapeutic, arts, and athletic programs supporting at-risk youth in residential treatment.
A proud member of the U.S. Marine Corps, Joseph served in the Marine Corps Reserve during the Gulf War era, trained at Parris Island and Camp Geiger, and remains committed to the values of discipline, courage, and service instilled during his military tenure.
Joseph holds a Master of Arts in History from the University of Massachusetts Boston, where his graduate thesis explored the intersections of public education, class, race, and equal opportunity. He also earned a Master of Science in Criminal Justice from Anna Maria College and a Bachelor of Arts in Political Science from UMass Boston.
Our Team
Our team consists of licensed and experienced private investigators who are dedicated to providing our clients with the highest level of service and professionalism.
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We look forward to serving you again!