Fake cyanide seller convicted over death of suicidal British man

'Sidney Kilmartin devised this malicious scheme to take advantage of the most vulnerable people,' says prosecutor

Mr Kilmartin is yet to be sentenced (AP)

An American has been convicted of supplying cyanide over the internet to a suicidal British man who used it to kill himself.

Sidney Kilmartin was found guilty of wire fraud, witness tampering, mail fraud and supplying the injurious substance, which killed Andrew Denton in 2012.

A jury in Bangor, Maine, concluded Mr Denton, from Hull, was one of many customers who had paid for the fatal drug.

However, in a bizarre twist, it emerged during the trial that - despite claiming he would sell potassium cyanide to customers who contacted him - on receiving payment, Mr Kilmartin would actually scam his customers by sending Epsom salts, a common laxative, according to the Hull Daily Mail.

When Mr Denton realised he had been sent the bogus drug, complained to Mr Kilmartin that he would report the business to the FBI.

Mr Kilmartin urged his customer to withdraw his threat and sent him a package containing enough cyanide to kill 20 people.

Mr Denton consequently took the fatal dose on New Year’s Eve and left a suicide note explaining the remainder of the drug was in a nearby plastic bag.

He advertised the cyanide on his website and invited customers to contact him by email.

Mr Kilmartin then encouraged his clients to send wire payments via Western Union or PayPal, explaining he would send the drug once payment was received.

Mr Kilmartin obtained the cyanide by posing as a goldsmith and approaching a company which provided chemicals to industrial clients. Cyanide is used to extract gold from its ore.

Mr Frank explained that the defendant “toyed with [his customers]. He chose who got to live, who got death."

Martin Ridge, Mr Kilmartin’s lawyer, maintained his client should not be held responsible for Mr Denton’s death: "Mr Denton died in the exact manner he wished to die. Mr Denton's death was caused by Mr Denton's actions.”

The date for Mr Kilmartin’s sentencing has not been set.