Federal authorities arrested a 28-year-old man in Kearny Monday morning after a months-long investigation determined he was selling highly addictive drugs online, officials said.

Chukwuemeka "Emeka" Okparaeke is charged with one count of conspiracy to distribute large quantities of fentanyl analogues, acting New York U.S. Attorney Joon Kim announced in a statement.

Okparaeke is accused of receiving several kilograms of fentanyl and repackaging the drugs into smaller quantities for resale. Authorities say he then sold the drugs through an online black marketplace on the "darknet" accessible only through special software that allows users to mask their identities with encryption and decryption to sell them.

Fentanyl, which is stronger than heroin and similar to morphine, is highly addictive and lethal if too high a dose is taken. The drug killed beloved pop star Prince, whose autopsy revealed he died of an accidental overdose in April.

The investigation -- by United States Postal Inspection Service, the Department of Homeland Security, and the Customs and Borders Protection -- began in Middletown, New York in November, according to Okparaeke's criminal complaint.

An employee at a Middletown post office reported that several postal workers saw a "suspicious person" wearing latex-dipped gloves leave several packages in a bin outside the building. Authorities were able to determine Okparaeke was similarly shipping packages from other nearby locations and using a fake return address, the complaint states.

Police in Virginia later ordered a package of drugs, which they received, from the black market account "Fentmaster," which authorities say belongs to the 28-year-old.

At some point the investigation led authorities to New Jersey, and Okparaeke's car was spotted outside a "townhouse" in Kearny on March 7, according to the court filings.

Authorities watched Okparaeke place two USPS crates into his car and leave the area. The investigators then went to the Harrison post office a few miles down the road to check for the packages they believed the 28-year-old had prepared to ship. Nearly 80 packages matched the name and address an undercover police provided to "Fentmaster," the complaint states.

Okparaeke was arrested on Monday morning and federal authorities wearing hazmat suits were at 344 Kearny Ave. for nearly 12 hours.

"Opioids such as fentanyl have become a public health crisis robbing many of productive futures and their very lives," USPIS Inspector in Charge Phillip R. Bartlett said in a statement. "Postal Inspectors have always made it their mission to protect the public and the U. S. Postal Service from these alleged drug traffickers, putting an end to their criminal enterprise through their misuse of the U. S. Mail."

The case is being heard in the United States District Court in White Plains, New York. Okparaeke faces 10 years to life in prison if convicted of the crime.

Caitlin Mota may be reached at cmota@jjournal.com. Follow her on Twitter @caitlin_mota. Find The Jersey Journal on Facebook.