A woman who gave birth under arrest and her boyfriend are facing weapons charges after authorities said they found a substance used to make bombs and papers entitled The Terrorist Encyclopaedia in their apartment.
Morgan Gliedman, the 27-year-old daughter of a prominent New York City doctor, and Aaron Greene, 31, were arrested on Saturday after officers with a search warrant swooped on the apartment in a picturesque Manhattan neighbourhood.
They discovered a plastic container with 7g of HMTD, a highly-explosive white powder used in bomb making, police and prosecutors said.
New York police commissioner Raymond Kelly said the substance was powerful, but it was difficult to speculate how much damage it would do in that amount.
Also found in the living room were numerous written items containing instructions on the manufacture of explosive materials and bombs, including a collection of pages that had a cover page, The Terrorist Encyclopaedia, and a booklet entitled Deadly Homemade Weapons, court papers said.
No political writings were discovered, and Mr Kelly said the investigation was continuing into whether the couple had any larger plans or ties to any radical groups. They did not show up on any watch lists.
Investigators also recovered a sawn-off shotgun, a commercial replica of a grenade launcher and ammunition, and chemical precursors to HMTD also were found in the living room, according to police and court papers.
Greene was held without bail after he appeared in state court in Manhattan on Sunday. Gliedman, who was nine months' pregnant when she was arrested, went into labour and gave birth to a baby girl named Melanie, police said. She was in hospital and had not yet appeared in court. A call to her family was not immediately returned.
Authorities said both defendants had drug problems.
"The whole situation's sad," said lawyer Lisa Pelosi, who represented Greene. Greene is due back in court on Friday.