A federal grand jury has indicted the man at the center of a large police search last month on new charges connected to false FBI credentials, the NBC10 Investigators have learned.

Eugene Horsch, 44, faces federal charges of possession of a firearm by a felon and possession of an unlawfully produced document and authentication feature, according to a copy of the indictment.

Federal park rangers arrested Horsch on June 19 on drug-related charges, according to court records. Information obtained after his arrest led investigators to search a home on West Chew Avenue from late Thursday into Friday.

The indictment includes charges connected to false DEA and FBI credentials, documents show.

Federal authorities seized the DEA credential during Horsch’s initial arrest. The FBI credential was found during the search, according to the documents.

Federal officials also seized a desktop computer.

Inside the Olney home Horsch shared with his late father, Ray Horsch, federal agents and DEA task force officers discovered “a lot of ammo and some narcotics,” Philadelphia police said in the aftermath.

Investigators also found evidence suggesting an attempt to grow or produce narcotics.

Among the items seized was a piece of writing about serial killer Ted Bundy that referenced zip ties and a drum, a source familiar with the investigation told NBC10. The note also mentioned killings and “trash that needs to go.”

It remains unclear who wrote it, though Eugene Horsch’s attorney suggested Ray Horsch was the author.

Horsch was transferred to federal custody after federal prosecutors charged him late last month. He also faces state charges connected to his June 19 arrest. A preliminary hearing in that case is scheduled for Aug. 6. A jury trial in the federal case was scheduled for Sept. 28.

DNA testing was underway on material seized from the Chew Avenue home, but investigators have not specified what evidence is being analyzed. A spokesperson for Philadelphia police said Thursday the investigation was ongoing. The FBI was also assisting in identifying the chemicals recovered from the home.

NBC10 investigative reporter David Charns can be reached at david.charns@nbcuni.com.