The office says Luis Soto, 29, was assembling guns inside his home on Tioga Street.
A raid was conducted by the attorney general's office and other law enforcement partners last week.
Soto was allegedly making "ghost guns" - ordering the parts online and then assembling them in his basement.
The D.A.'s office said Soto was arrested after selling three "unregistered and untraceable" ghost guns to a police informant.
Inside his home, investigators allegedly found another completed "ghost" handgun, various firearm parts and firearm assembly tools, boxes containing 9mm rounds, .22 caliber rounds, .50 caliber rounds, as well as one partially-assembled "ghost" AR-style rifle.
"The laws need to be able to change so we can stop them at the point of sale, because a felon should not be able to purchase parts and put a gun together in his home," said Asst. District Attorney William Fritze.
The D.A.'s office says Soto is a five-time felon and was not allowed to possess firearms.
He is being held on $875,000 bail.