Malachi Johnson plunged from the balcony while playing outside Friday night, the New York Daily News reported. His mother was inside the family's apartment at the time.
"Malachi was a strong boy and very smart," his father, Hardwick Johnson, said Saturday. "I want to know how he fell off the balcony and if the balcony was safe."
Balconies in the Johnsons' building were inspected earlier this year as part of a citywide program following the death of a Manhattan man in a fall from a balcony. Tony Sclafani, a spokesman for the Department of Buildings, said inspectors found the Johnsons' balcony was structurally sound, although problems were found in other apartments.
Co-op City, the world's largest cooperative housing project, was built on the site of a former amusement park in the far northeast Bronx between 1968 and 1973.