A US citizen could face life in jail for allegedly sending cyanide to a man in Hull who used it to kill himself two years ago.
Andrew Denton, 49, who was suffering from depression, was found dead at his home in Holland Street on New Year’s Eve 2012.
Following a transatlantic investigation Sidney Kilmartin, 52, was arrested by federal agents on Wednesday, in Maine, in the US.
He is alleged to have sent Mr Denton a faulty batch of potassium cyanide first time which failed to work, before a second batch was sent.
If found guilty Kilmartin could serve anything from 20 years to life in jail.
An investigation involving the U.S Postal Inspection Service started after officers investigating his death found the chemical, which looks like sugar, at the scene.
A colourless crystalline salt, used in gold mining, it was used by members of the Nazi Party, such as Hermann Göring and Heinrich Himmler to committ suicide.
It was later identified through tests by the Chemical, Biological, Radiological and Nuclear Unit and specialists at Humberside Fire and Rescue Service.
A former soldier, Mr Denton had made numerous suicide attempts to including taking a drug overdose and trying to hang himself.
Blood taken from his body showed it had more than three times the lethal amount of the drug.
Analysis of mobile phone messages and his laptop seized from his home showed there had been correspondence with someone from Maine using a pseudonym. The series of messages ended with Mr Denton complaining about the quality, with more of the drug being sent which Mr Denton took to end his life. The investigation was handed over to US Postal Inspection Service as the offence included the misuse of the US Mail system.
Postal Inspector Michael Desrosiers, who visited the city in June as part of the investigation, said: “In my 28 years as an Inspector I have never come across Potasium Cyanide being mailed and it is even rare that it has led to a homicide. During the case Humberside Police showed total cooperation with the investigation and have left no stone unturned in assisting in the prosecution. Detective Constable Stu Quinn and the rest of the Critical Incident Team have been fantastic.
“The case highlights that we work with our international law enforcement partners to ensure U.S. Postal System is not used by criminals. If people do post item’s which contravene the law they can and will face being arrested and in cases like this face a considerable sentence.”