Dalien Enrique Nieves-Santiago, Fentanyl Trafficking, Puerto Rico 2025

A Naranjito man has been sentenced to seven years in prison for his role in a fentanyl trafficking operation. Dalien Enrique Nieves-Santiago, 38, and his wife Zuleyka M. Santiago-Andino, 35, were charged in a superseding indictment on December 6, 2023, and pleaded guilty on June 5, 2025.

According to court documents, Nieves-Santiago pled guilty to possession of a punch and die set, conspiracy to possess with intent to distribute fentanyl, and possession of firearms in furtherance of a drug trafficking crime.

The investigation began on April 14, 2023, when Customs and Border Protection (CBP) Officers in San Juan, Puerto Rico encountered a UPS package while conducting inspections of inbound parcels. The package, shipped from an address in China, was addressed to defendant Zuleyka M. Santiago-Andino.

Upon further inspection, CBP Officers discovered a ‘pill die’ set inside the package. A ‘pill die’ is used with a pill press to cut and mark narcotic tablets and other such controlled substances in a pill or tablet form and used in the furtherance of manufacturing and distribution of controlled substances including, but not limited to, pills such as Oxycodone.

HSI and DEA agents executed a court authorized search warrant at the residence of Nieves-Santiago and seized approximately 2 kilograms of a blue colored bonding agent, approximately 302 grams of Xanax pills, and a small scale. They also recovered two firearms: a 9 mm Smith & Wesson pistol, one 9 mm magazine and eleven (11) 9 mm rounds of ammunition; and a loaded .40 caliber Glock pistol, three (3) .40 caliber magazines, and twelve (12) .40 caliber rounds of ammunition next to 1,037 Xanax pills.

A laboratory analysis concluded that a total net weight of 286.51 grams from the 1,037 white rectangular pills with ‘Xanax’ imprinted on one side and ‘2’ on the other side. The substances identified in the pills were fentanyl. A total net weight of 1,921.15 grams of the blue bonding agent typically used to manufacture Oxycodone Hydrochloride tablets with the use of a pill die.

Nieves-Santiago was sentenced to seven years in prison and five years of supervised release. His wife, Zuleyka M. Santiago-Andino, also pleaded guilty to drug trafficking and possession of a pill press die and will be sentenced at a later date. Assistant United States Attorney Luis A. Valentin from the Asset Recovery, Money Laundering and Transnational Organized Crime Unit prosecuted the case.

The investigation was conducted by Immigration and Customs Enforcement Homeland Security Investigations, Customs and Border Protection, and the Drug Enforcement Administration.

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