Police arrested a New York City couple in their apartment on Saturday after authorities investigating a credit card theft found a highly explosive compound, bomb-making manuals, a sawed-off shotgun and ammunition, officials said on Monday.

Morgan Gliedman, 27, and Aaron Greene, 31, are being charged with two counts of suspicion of criminal possession of a weapon, for the shotgun, court documents show.

One sheaf of papers found in the apartment had a cover page that read “The Terrorist Encyclopedia,” according to court documents.

Greene has been arraigned and held without bail, according to a law enforcement official involved in the investigation, who was not authorized to discuss the ongoing investigation.

Gliedman had not yet been arraigned on Monday morning, said a spokeswoman for Manhattan District Attorney Cyrus Vance Jr.

Police went to the couple’s Greenwich Village apartment Saturday to question Gliedman, the daughter of a prominent New York doctor, to investigate a credit card theft, according to a second law enforcement official.

At the apartment, detectives discovered a plastic bottle containing seven grams of Hexamethylene triperoxide diaminean, or HMTD, court documents show.

HMTD is commonly used in homemade bombs. The discovery prompted the evacuation of nearby buildings, the second source said.

Police also discovered a cache of bomb-making manuals and handwritten notebooks containing chemical formulas, the second source said.

Additionally, investigators recovered a 12-gauge Mossberg 500 shotgun, ammunition, nine high-capacity rifle magazines and a flare launcher, the second source said.

Law enforcement officials said Gliedman was the son of Paul Gliedman, director of radiation oncology at Beth Israel Hospital in Brooklyn.

Neither Gliedman nor his wife, Susyn Schops Gliedman, a Douglas Elliman realtor, returned calls for comment.

Morgan Gliedman studied creative writing at The School of The Art Institute of Chicago, according to her Facebook page, which contains a photo of Gliedman outside a pink dressing room, posing in a black, scoop-neck sweater and red checkered skirt.

Greene attended Harvard University in Cambridge, Massachusetts, according to the New York Post, which first reported the arrests.

The newspaper quoted a law enforcement source as saying that Greene was an Occupy Wall Street activist whose political views were “extreme.”

Two spokesmen for Occupy Wall Street’s New York chapter said they had no knowledge of Greene.

(AP)