Investigators say Sidney Kilmartin of Windham advertised and mailed a substance he claimed was cyanide to several suicidal people. The substance was actually Epsom salt.

But they say he mailed the real thing to Andrew Denton of Hull, England, to keep him from telling investigators about his moneymaking scheme. Denton used the cyanide to take his life.

Kilmartin, who was due in federal court Tuesday, was originally indicted on charges of mailing injurious articles resulting in death. A grand jury last month returned indictments on new charges of witness tampering and witness retaliation.