Investigators seized $8 million worth of heroin from an alleged heroin packaging mill in a Bronx apartment Wednesday, authorities said. 

NYPD officers and Drug Enforcement Administration agents were staking out a possible drug transaction at 181 W. 238th St. when they noticed three men leaving the building with a heavy blue bag and leaving in a black Acura with Pennsylvania license plates, accordinig to officials. 

Investigators found $130,000 worth of heroin in the backseat and arrested Carlos Castillo of Manhattan, and Bladimar Ramirez-Ramirez and Adalberto Cotts-Perz of Hazelton, Pa.

Police and drug agents later executed a search warrant at the apartment and seized 11 kilograms of heroin, officials said.

DEA Special Agent in Charge Brian R. Crowell said heroin traffickers were a top priority for the agency in New York.

"The first destination for bulk heroin in the NYC area, which is what we seized last night, is the first link along a long distribution chain where the bulk heroin is cut and packaged for wholesale," Crowell said in a press release, adding that heroin and pain pills sold in the illegal drug market were causing the most harm to New Yorkers.

The suspects' attorneys were not immediately available as the men were awaiting an appearance in Manhattan Criminal Court.