The woman called 911 on Saturday night about a foul odor coming from her grandson's room at her home on 2400 Seventh Ave near West 140th Street.
Authorities later discovered a 55-gallon drum with a body inside, sources said.
The clothed body was stuffed inside the drum, so police weren't immediately sure whether the victim was male or female, sources said.
Khylisha Brooks' family lives next to the apartment where the body was discovered. She says her neighbors kept to themselves.
"I do not want to be here at this moment at all, it's uncomfortable," said Brooks.
Like many residents Eyewitness News talked to, Brooks says she is unnerved by the details of the crime.
Brooks says she can't get her mother to leave her apartment.
"She doesn't want to come out of the houses, it's horrible, very horrible," Brooks adds.
No one has been arrested or charged in the case.
Sources tell Eyewitness News that they have yet to question the grandson. He is currently at St. Luke's Hospital undergoing a psychiatric evaluation.