Authorities said Dominick Calhoun of Argentine Township died after a beating that stretched over four days in April 2010.
Brandon Hayes was tried in Port Huron in St. Clair County because Genesee County officials couldn’t seat a jury there.
On Thursday, jurors found Hayes guilty of first-degree felony murder, torture, child abuse and drug counts. Hayes faces sentencing Feb. 27. The murder conviction carries a mandatory penalty of life in prison without possibility of parole.
Dominick died a day after being found unconscious. His mother Corrine Baker pleaded guilty to second-degree murder and child abuse.