Jomali Morales was found stabbed to death on the floor of an elevator in the Baruch Houses on February 12. Now, 19-year-old Markeece Dunning has confessed to the murder.
Dunning lives in the complex, but it is unclear if he and Morales knew each other.
Morales was stabbed about 20 times.
Dunning is charged with second-degree murder.
"She was like a light that lit up the room," Morales' mom Petra Vitale said. "And that smile!"
Petra says her daughter grew up on the Lower East Side and was an aspiring fashion model before moving out of town, where she married and raised a daughter.
She came back to New York and was living with Petra in her co-op apartment when she disappeared.
Police say Dunning has 11 prior arrests for various crimes, including drug possession, trespassing and gang assault.