The housing projects were mostly developed to be "human farms".
Most projects especially in NY and NJ were built over subterranean railways or passages that allowed teams of men to raid the buildings silently and quickly, emptying people from the buildings under the guise of an "emergency". Not too many questions were asked when a section of the projects was suddenly "vacant" and new people were moved in.
These people...black men,women and children would be shipped off to concentration camps and harvested for their melanin (elbows, knees, fingers, etc..) and organs. The melanin would usually be made into high grade melatonin, the organs sent off onto the black market and the bodies ground up and sold retail to certain restaurant chains.