Police said they had detained a "person of interest" in the killing.
Relatives, who identified the boy as Jakari Pearson, told the Detroit News the shooter may have been a man who was angry at his mother for breaking up with him. Police released few details.
"The person we are talking to has not been arrested or been identified as a suspect in the shooting," Sgt. Mike Woody said. "He's nothing more than a person of interest in this case and is being interviewed. He did not voluntarily come to us but was found through good, old-fashioned police work, plus tips from the community."
Jakari died at a hospital shortly after the shooting.
Beatrice Spears, who said her sons went to the same school as Jakari and were in the same baseball league, told the News she heard gunfire, followed by the mother's screams. When she went outside, she saw the boy on the porch while his family and police officers waited for an ambulance to arrive.
"I just know now the kids are going to be terrified," she said.