A half-eaten container of ice cream led Portland police to an alleged killer.

Frederick Johnson, 46, allegedly strangled 23-year-old Bethany Kelley behind a car on Kennebec Street in Portland’s Bayside neighborhood last November.

Johnson and Kelley were both homeless. Johnson was arrested in February and charged with murder. He was already in custody at the Aroostook County Jail in Houlton on unrelated charges when Portland police issued a warrant for his arrest.

Johnson bought a container of cookies and cream ice cream earlier that night, and the partially eaten ice cream was found next to Kelley’s body, according to court documents.