Charges against the Sudbury man accused in the death of Stephen Rakes, one of James “Whitey” Bulger’s extortion victims, were upgraded to murder Friday, said Middlesex District Attorney Marian T. Ryan. William Camuti, 69, was indicted Oct. 3 on charges of attempted murder, misleading police, and unlawful disposition of human remains. But the charges were upgraded after an autopsy indicated that the cause of death was acute cyanide toxicity and the manner of death was homicide, said a statement from Ryan’s office. Prosecutors say Camuti killed Rakes in July when he poisoned his iced coffee and later discarded his body in Lincoln.Haven Orecchio-Egresitz can be reached at Haven.firstname.lastname@example.org. Follow her on Twitter @HavenTaylor.