By Dave Sherwood
PORTLAND Maine (Reuters) - A Maine resident with a history of mental illness mailed a second, heavier dose of cyanide to a British suicide victim after the initial shipment failed to kill him, British police said on Friday.
Sidney Kilmartin pleaded not guilty on Wednesday after he was arrested on U.S. charges that he had supplied Andrew Robert Denton, 49, of Kingston-upon-Hull in northeast England with the poison after arranging the deal online, causing Denton's death in 2012.
A 2-year trans-Atlantic investigation revealed that Kilmartin shipped cyanide 3,000 miles to Denton for a second time after he survived the first dose and complained of its quality, police in England said in a statement.
The second shipment allowed Denton to inject more than three times the dose classified as lethal into his bloodstream, police said. Denton was found dead in his home Dec. 31, 2012.
The U.S. Postal Service inspector who helped investigate the shipment, Michael Desrosiers, said the case was unprecedented: "In my 28 years as an inspector I have never come across potassium cyanide being mailed."
Potassium cyanide is a rare and highly toxic white or crystalline substance that interferes with the body's ability to use oxygen, according to the U.S. Centers for Disease Control and Prevention.
Kilmartin is scheduled to appear again in court on Nov. 14.
Kilmartin was living at home under psychiatric supervision when he was arrested, police said.
In 2007, Kilmartin was arrested on unrelated charges of burglary and assault but found not criminally responsible by reason of insanity, according to court filings.
(Writing by Richard Valdmanis; Editing by Richard Chang)