NEW YORK (CBSNewYork) – A 20-year-old man is accused of throwing his much younger brother off the roof of their Brooklyn apartment building.

Police say the victim, who was just four years old, died at the scene.

Shawn Smith was walked out of the 70th Precinct in handcuffs Saturday evening after the NYPD said he confessed to throwing Shimron Smith from the roof of the Nostrand Avenue apartment building around 3:30 in the morning. He has been charged with second degree murder.

20-year-old Shawn Smith accused of throwing brother off roof. (Credit: CBS2)

Neighbors claim the man was known to have mental health problems.

“He just walked around. Never really spoke to nobody,” Benny Isakajv told CBS2’s Lisa Rozner. ”They say he had schizophrenia so I guess that got the best of him.”

First responders found Shimron unconscious and unresponsive in the building’s courtyard. The community remembered the boy with a growing memorial outside his home Saturday.

“I have a little one myself. I can’t fathom somebody taking my child and throwing him off the roof like that,” Donna Hayward said. “It tears me apart. It hurts me to the core to even hear it.”

CBS2 saw police speaking with the family earlier in the day however, their investigation into what led to the child’s death is ongoing.