NEW YORK (CBSNewYork) — Authorities seized more than 55 pounds (approximately 25 kilograms) of suspected heroin and fentanyl late Wednesday night from a Bronx apartment that allegedly served as a drug packaging mill, law enforcement officials said.

The drugs, worth an estimated $7.5 million, were taken from a two-bedroom apartment on Morrison Avenue in the Soundview neighborhood of the Bronx.

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Agents recovered 11 kilograms of suspected heroin was found in one bedroom closet, another 10 kilograms hidden in a wall and approximately 230 grams of heroin in a dresser.

In the other bedroom, agents found a variety of equipment used to process the narcotics for street-level distribution, including 100 different ink stamps for branding individual dose envelopes, according to the city’s Special Narcotics Prosecutor’s office.

Names on the stamps included, “Kill,” “Death,” “100%,” “UPS,” “Heartless” and “Super High.”

Prior to the search, agents and investigators were conducting surveillance in the area when they observed Luis Guzman-Rojas, 46, enter the apartment building at around 8:20 p.m. Wednesday and leave shortly after with a black plastic shopping bag.

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They followed the livery car that drove Guzman-Rojas away and stopped it at the corner of Bruckner Boulevard and Hunts Point Avenue. Guzman-Rojas was arrested after agents and investigators observed him in the back seat with plastic-wrapped kilogram of suspected heroin marked with the letters “LV” and the same shopping bag he carried from the apartment building, the prosecutor’s office said.

The Special Narcotics Prosecutor’s Office got a search warrant for the apartment and went in at approximately 11:05 p.m., officials said.

Four men found in the apartment’s living room area — Matias Rosario-Ramon, 37, Anthony Polanco, 29, Willy De La Cruz, 28, and Pedro Sandoval, 26 — face charges of criminal possession of a controlled substance and criminally using drug paraphernalia.

Guzman-Rojas is charged with criminal possession of a controlled substance, officials said.

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The Special Narcotics Prosecutor’s Office conducted the raid with the New York Drug Enforcement Task Force, which includes agents and officers with the federal Drug Enforcement Administration, NYPD and the New York State Police.