Two men are in federal custody after they were allegedly caught with 44 pounds of an opioid up to 50 times more powerful than heroin, authorities said Monday.

Luis Aponte, 48, and Denny Diaz, 29, were charged with one count of conspiracy to possess fentanyl with intent to distribute, U.S. Attorney Craig Carpenito said in a statement.

Aponte, of Hesperia, California, was spotted by Drug Enforcement Administration agents Friday at a rest stop in Bloomsbury in Hunterdon County, Carpenito said. I-78 cuts through the northern end of town. Aponte parked the tractor-trailer at the rest stop overnight, authorities said.

The agents saw Aponte carrying a backpack on Saturday when into a white SUV driven by Diaz, of Philadelphia, Pennsylvania, authorities said. As the vehicle pulled away, agents saw Aponte take a plastic bag out of the backpack and put it behind the driver’s seat, authorities said. The vehicle then pulled onto the shoulder before law enforcement approached, authorities said.

The vehicle was searched and the agents found about 15 pounds of fentanyl in the plastic bag, along with $17,000 in cash in the backpack. They arrested Diaz and Aponte, who later waived his Miranda rights and said he had more drugs in the tractor-trailer. Agents searched the truck cab and a refrigerator on board and found another 29 pounds of fentanyl and 11 pounds of heroin.

Aponte and Diaz made initial court appearances in Newark federal court Monday before U.S. Magistrate Judge Joseph Dickson. They were held without bail.

If convicted, they face a mandatory minimum of 10 years in prison.

Joe Brandt can be reached at jbrandt@njadvancemedia.com. Follow him on Twitter @JBrandt_NJ. Find NJ.com on Facebook.

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