(CNN) -- A 69-year-old Massachusetts man was arrested and charged Friday in Boston in connection with the death of Stephen Rakes, a regular at James "Whitey" Bulger's trial before he was found dead last month near a walking trail, authorities said.
William Camuti was taken into custody in Boston and charged with attempted murder, misleading police and unlawful disposition of human remains, the Middlesex District Attorney's office announced in a press release.
His attorney couldn't be immediately reached for comment.
The body of the 59-year-old Rakes was found July 17 in a wooded area in Lincoln, Massachusetts, about 30 miles from his home in Quincy.
Rakes had been an alleged extortion victim of Bulger's, and had learned shortly before his death that prosecutors no longer planned to call him to testify, according to a friend.
Bulger, a reputed Irish mob boss in south Boston, is now standing trial in that city for allegedly participating in 19 murders, racketeering, money laundering and extortion over a two-decade period.
Camuti and Rakes were longtime business associates, and Camuti allegedly poisoned Rakes at a time when Camuti owed money to Rakes.
"We allege this defendant intentionally put poison in the victim's iced coffee and then disposed of his body," Middlesex District Attorney Marian Ryan said in a statement.
In a phone call on July 16, Camuti asked Rakes for a meeting to discuss a potential investment property in Wilmington, Massachusetts, authorities said.
In fact, the investment deal was fake, authorities said.
On the same day, surveillance video showed Rakes leaving the federal courthouse where he regularly attended Bulger's murder trial. Rakes appeared to be wearing the same clothing in which his body was found, authorities said.
The two men met that afternoon in a McDonald's in Waltham, and Camuti bought two iced coffees, one of which he allegedly laced with two teaspoons of potassium cyanide and gave to Rakes, who drank it, authorities said.
Camuti allegedly drove Rakes around the cities of Waltham, Woburn, Burlington and Lincoln for several hours.
Investigators alleged Camuti dumped Rakes' body in the wooded area, where it was found the next day.
The medical examiner's office has yet to determine the cause of Rakes' death, authorities said.
CNN's Michael Martinez and Greg Botelho contributed to this report.