United States Drug Enforcement Administration

BOSTON – A Dominican national residing in Lawrence has been arrested and charged for his alleged involvement in a North Shore-based drug trafficking organization (DTO) that distributed fentanyl and methamphetamine supplied by the Sinaloa Cartel. 

Leury Then Rosario, 33, was charged with conspiracy to distribute and to possess with intent to distribute 400 grams or more of fentanyl and methamphetamine. Rosario was arrested on Feb. 25, 2025 and was ordered detained pending a hearing scheduled for March 7, 2025. 

“The alleged discovery of this defendant’s hidden trap wall concealing a stockpile of narcotics and weapons lays bare the dangerous reality of drug trafficking today: fentanyl and methamphetamine are flooding our communities, protected by deadly firepower,” said United States Attorney Leah B. Foley. “Drug traffickers are adapting, but so are we. This office, alongside our law enforcement partners, will continue to dismantle these criminal networks piece by piece, ensuring those who peddle poison in our communities face the full force of justice.”

“Those who choose to distribute fentanyl, especially fake pills containing the drug, endanger their customers as well as the general public. Maintaining public safety requires that they be investigated and prosecuted aggressively,” said Stephen Belleau, Acting Special Agent in Charge of the Drug Enforcement Administration, New England Field Division." We work closely each day with our law enforcement partners to target those who seek to profit from the sale of deadly substances.”

“The Massachusetts State Police has committed investigatory, intelligence and tactical resources in support of the DEA Strike Force, knowing that it could yield enormous results for the communities we serve,” said Massachusetts State Police Colonel Geoffrey Noble. “This arrest, the second successful operation in as many weeks, is a culmination of a complex investigation by local, state and federal partners. Their results and the decision to prosecute these offenses reinforce our shared belief that criminal gangs, illegal guns and illicit drugs have no place in Massachusetts. We remain steadfast in our commitment to ensuring the safety and security of our communities.”

According to the charging documents, in January 2023, an investigation began into a DTO operating on the North Shore area of Massachusetts that was being supplied with fentanyl and methamphetamine by an organization based in Sinaloa. The investigation allegedly identified Rosario to be a Lawrence-based drug trafficker operating as part of the DTO.  

Immediately following Rosario’s arrest on Feb. 25, 2025, search warrants were executed at his primary residence and an alleged stash location in Lawrence, Mass. It is alleged that the stash location purported to be a multiservice business with an empty retail counter in the front room. The back room allegedly contained two large casino-style poker tables and video poker-type machines. A high-end video surveillance system was allegedly overserved operating throughout the first floor as well as outside. According to court filings, the basement storage room of the stash location contained two large, locked storage boxes that contained equipment commonly used in drug processing or manufacturing: respirators; gloves; drug packaging materials; scales; blenders; and other tools. 

According to court documents, a small remote control with an extendable antenna was also allegedly found. When law enforcement actuated the remote control, an audible alarm sounded and a trap wall within the storage area opened – revealing a hidden closet that allegedly contained, among other things:

• Over 16 kilograms of counterfeit pills, in various colors and sizes, containing controlled substances;
  • A brick-shaped object of a white powdery substance, weighing approximately one kilogram, that field tested positive for the presence of cocaine;
  • Over two kilograms of suspected fentanyl pressed into 10-gram units, commonly referred to as “fingers” in retail drug trafficking;
  • Over two kilograms of suspected fentanyl powder in large bags;
  • Over 25 pounds of loose powders in various colors, believed to include cutting agents used with narcotics;
  • A commercial pill press used to press counterfeit pills, including over 50 pill die casts with designs to counterfeit Percocet, Xanax, Adderall and others;
  • Multiple kilogram presses, as well as branded stamps used to imprint logos onto kilograms of narcotics;
  • One Glock Model 33 .357 caliber semiautomatic handgun loaded with six rounds of ammunition;
    • One High Point .380 caliber semiautomatic handgun loaded with eight rounds of ammunition;
    • One Ruger .380 caliber semiautomatic handgun loaded with six rounds of ammunition;
    • Two Glock-style personally made firearms (also known as “ghost guns”) with no serial numbers loaded with 10 and nine rounds of ammunition respectively; and;
    • One AR-15 style rifle with a .458 SOCOM caliber, loaded with eight rounds of ammunition.

The charge of conspiracy to distribute and to possess with intent to distribute 400 grams or more of fentanyl and methamphetamine provides for a sentence of at least 10 years and up to life in prison, at least five years and up to a lifetime of supervised release and a fine of up to $10 million. The defendant is subject to deportation upon completion of any sentence imposed. Sentences are imposed by a federal district court judge based upon the U.S. Sentencing Guidelines and statutes which govern the determination of a sentence in a criminal case.

U.S. Attorney Foley, DEA Acting SAC Belleau and MSP Colonel Noble made the announcement. Valuable assistance was provided by the Natick, Newton, Waltham, Brookline and Lawrence Police Departments. Assistant U.S. Attorney Charles Dell’Anno of the Narcotics & Money Laundering Unit is prosecuting the case.

This operation is part of an Organized Crime Drug Enforcement Task Forces (OCDETF) Strike Force Initiative, which provides for the establishment of permanent multi-agency task force teams that work side-by-side in the same location. This co-located model enables agents from different agencies to collaborate on intelligence-driven, multi-jurisdictional operations to disrupt and dismantle the most significant drug traffickers, money launderers, gangs, and transnational criminal organizations. OCDETF identifies, disrupts and dismantles the highest-level criminal organizations that threaten the United States using a prosecutor-led, intelligence-driven, multi-agency approach. Additional information about the OCDETF Program can be found at https://www.justice.gov/OCDETF.

The details contained in the charging documents are allegations. The defendant is presumed innocent unless and until proven guilty beyond a reasonable doubt in a court of law.