Jalique Keene, 21, is charged with murdering and sexually assaulting 19-year-old Mikaela Conley.
Her body was found near a school playground during a search in June.
Officials said Keene and Conley knew each other from their time living on Mount Desert Island and that the alleged killing happened soon after Keene returned from playing professional football in Serbia.
An autopsy determined that Conley died from blunt force trauma to the head and strangulation.
Keene has been held without bail since his arrest.