Leah B. Foley United States Attorney for the District of Massachusetts | Department of Justice
An associate of the Boston-based H Block gang has pleaded guilty to drug conspiracy charges in federal court. Mark Linnehan, 26, from West Roxbury, admitted to conspiracy to distribute and possess with intent to distribute controlled substances. U.S. District Court Judge Leo T. Sorokin set sentencing for April 7, 2026.
Linnehan was among ten H Block members and associates charged in August 2024 after a multi-year investigation that began in 2021. The investigation was launched due to an increase in gang-related drug trafficking, shootings, and violence connected to the group. Authorities seized over 500 grams of cocaine, crack cocaine, fentanyl, and more than 20,000 doses of drug-laced paper during the operation.
Law enforcement linked twelve gunfire incidents since 2021 to tensions involving H Block associates. Six members were arrested and charged with drug offenses in Boston and nearby areas; four others were already held in state custody at the time of these arrests. Additional drugs and four firearms were recovered during subsequent law enforcement actions.
From 2022 through 2023, Linnehan participated in distributing controlled substances—mainly fentanyl and cocaine—and supplied fentanyl to co-conspirators. He also conducted several drug transactions with an undercover officer.
The H Block Street Gang is described as one of Boston’s most influential gangs. Formed originally as the Humboldt Raiders in Roxbury during the 1980s, it re-emerged as H Block in the early 2000s. Members have a history of violent confrontations with police; notably, a member shot a Boston Police officer at close range without warning or provocation in a 2015 incident.
A conviction for conspiracy to distribute and possess with intent to distribute controlled substances carries up to twenty years’ imprisonment, supervised release ranging from three years up to life, and fines up to $1 million. Sentencing will be determined by federal guidelines.
Linnehan is now the ninth defendant to plead guilty in this case.
"United States Attorney Leah B. Foley; Jarod A. Forget, Special Agent in Charge of the Drug Enforcement Administration, New England Field Division; Randy Maloney, Special Agent in Charge of the U.S. Secret Service, Boston Field Office; Ted E., Docks, Special Agent in Charge of the Federal Bureau of Investigation, Boston Division; Boston Police Commissioner Michael Cox; and Russell W. Cunningham Special Agent in Charge of the Department of Justice Office of the Inspector General Mid-Atlantic Region made the announcement."
The case was prosecuted by Assistant United States Attorney John T. Dawley from the Organized Crime & Gang Unit and Jeremy Franker from the Justice Department’s Violent Crime & Racketeering Section.
The investigation was conducted under the Organized Crime Drug Enforcement Task Forces (OCDETF), which targets major criminal organizations using coordinated efforts across agencies led by prosecutors and intelligence teams. More information about OCDETF can be found at https://www.justice.gov/OCDETF/.
Authorities emphasized that all details contained within charging documents are allegations unless proven beyond reasonable doubt for remaining defendants.
