The Middlesex District Attorney's office confirmed an earlier report that the cause of death of Stephen Rakes, who was to be a witness in the Whitey Bulger trial, to be acute cyanide toxicity.
According to a spokesperson in the DA's officer, the manner of death is homicide.
Currently, William Camuti, 69, a former Sudbury resident, is facing charges of attempted murder, misleading police, and unlawful disposition of human remains in the Rakes case. The attempted murder charge was pending the toxicology report.
"We plan to seek additional charges," the spokesperson said.
The body of Rakes, 59, was discovered at 1:30 p.m. on July 17 in a wooded area off Mill Street in Lincoln.
Authorities believe Camuti poisoned Rakes over a bad business deal.