(CNN) -- The Massachusetts Medical Examiner's Office officially determined that the cause of death of an alleged Whitey Bulger extortion victim was homicide by cyanide poisoning, according to MaryBeth Long, a spokeswoman for the Middlesex District Attorney's Office. The office plans to seek additional charges against William Camuti -- who has already been charged with attempted murder, misleading police and unlawful disposition of human remains --- as a result of the official autopsy report. Camuti, 69, confessed to putting potassium cyanide in an iced coffee that he provided to Stephen Rakes, 59, according to a testimony by a Massachusetts state trooper at hearing in Concord District Court on September 10.
@highlight
Stephen Rakes was a regular visitor to the trial of mob boss James "Whitey" Bulger
@highlight
Rakes' business associate, William Camuti, has been charged in his death
@highlight
With cyanide report, Middlesex District Attorney's Office plans additional charges
@highlight
Trooper: Camuti confessed to slipping poison into Rakes' coffee at a McDonald's
Stephen Rakes
Stephen Rakes
Rakes
@placeholder took only one sip before deciding the coffee tasted too bitter.
William Camuti
Camuti
William Camuti
Camuti
@placeholder is being held without bail for 90 days after a judge deemed that his release would not "reasonably assure the safety of any other person or community," said Long.
William Camuti
Camuti
William Camuti
Camuti
Camuti and Rakes were longtime business associates, and @placeholder allegedly poisoned Rakes at a time when Camuti owed Rakes money.
Rakes
Camuti and Rakes were longtime business associates, and Camuti allegedly poisoned @placeholder at a time when Camuti owed Rakes money.
William Camuti
Camuti
William Camuti
Camuti
@placeholder pleaded not guilty to the charges at his arraignment in August.
Stephen Rakes
Stephen Rakes
Rakes
@placeholder had been a reported extortion victim of Bulger's and had learned shortly before his death that prosecutors no longer planned to call him to testify, a friend said.