Morgan Gliedman, 27, who is nine-months pregnant, and her boyfriend, Aaron Greene, 31, were arrested Saturday afternoon after police allegedly found the cache in the couple's home, the New York Post reported.
Police were called to the couple's apartment because Gliedman, the daughter of a prominent New York City doctor, was wanted for alleged credit-card theft. Once there, police found a flare launcher, a modified 12 gauge Mossberg 500 shotgun, ammunition and nine high-capacity rifle magazines, police officials said.
Police also allegedly found seven grams of a white chemical powder called HMTD -- powerful chemical that prompted officers to evacuate several nearby buildings -- as well as note on how to make homemade booby traps, improvised submachine guns, and various handwritten notebooks containing chemical formulas.
2014: The Year in Music [PHOTOS]