WARREN, Ohio (WKBN) — A city man is being held in federal detention after an affidavit said he received a package of drugs in the mail this week and authorities were able to track him and the package.

Robert Lang, 29, faces a charge of attempted possession with intent to deliver a controlled substance. He is presently being held in the Mahoning County Jail pending a detention hearing in the U.S. Northern District Court of Ohio.

Lang was arrested Wednesday after federal authorities tracked a package that was delivered to him from a home on Clearwater Street NW to Stephens Avenue NW. A criminal complaint was filed against him Thursday.

Earlier in the day, federal agents got a search warrant after a package delivered to a FedEx facility in Cleveland addressed to the Clearwater Street NW home was found to have fentanyl inside.

Agents replaced the fentanyl with a fake substitute and delivered the package themselves then watched the home where it was delivered, an affidavit in the case said. Agents installed a tracking device in the package and an invisible dye was also sprayed on the package that would show up on anyone who handled it.

The affidavit said Lang went to the Clearwater Street NW home, got the package, and took it to the Stephens Avenue NW home, where authorities stopped him after he got there. Reports said the package was opened and an examination with an ultralight device showed Lang had the dye on him from handling the package.

The affidavit said Lang was questioned and he admitted picking up the package but said he did not know what was supposed to be inside. Lang also admitted to receiving three prior packages from the same sender that had drugs in them, the affidavit said.