The boy, whose name was not reported, was caught stealing from a nearby store shortly before the incident Wednesday, the Detroit Free Press reported.
His 15-year-old sister found out about the theft and told him he was going to get a spanking when he returned home, said Pastor Barak Holmes Jr., a member of the boy's extended family. When he got home, the boy ran to his room. His sister then saw his body on the ground outside when she got close to the window.
"This is a very, very tragic incident," Holmes said. "It's terribly unfortunate."
Police said their investigation indicates the boy either jumped or fell from a window in the family's high-rise apartment. The boy had made threats to commit suicide in the past, but police did not say when that happened.
It was not reported whether an autopsy had been performed.