It will likely be weeks before it is known for certain how the phone-hacking whistleblower Sean Hoare died, police said yesterday evening.
The former showbiz reporter at the News of the World, who was the first journalist there to claim that Andy Coulson had knowledge of phone hacking, was found dead on Monday at his home in Watford, Hertfordshire, after friends raised concerns over his whereabouts.
His death came after a series of explosive newspaper interviews in which he exposed the "dark arts" employed by journalists at the tabloid.
It is understood that no suicide note was found. He was known to be battling an addiction to alcohol.
Hertfordshire police said that there were no suspicious circumstances surrounding Mr Hoare's death, but were awaiting the results of toxicology report to determine exactly how he died. Such examinations can often take up to three weeks.
A police spokesman said: "There is no evidence of third-party involvement and the death is non-suspicious. Further toxicology results are now awaited and there is an ongoing examination of health problems identified at the post-mortem."
Although Mr Hoare was known to be struggling with health problems, friends said he had become increasingly "paranoid" that "people were coming for him" in the days leading to his death.
In one of the most sensational interviews, with The New York Times last year, he claimed that his former friend and editor, Mr Coulson, had actively encouraged him to hack into voicemails while he was working at NOTW.
On the night after his death, he also appeared in a BBC documentary and a daily broadsheet in which he sought to "set the record straight" over the improper news-gathering techniques that were allegedly encouraged by senior staff at the paper.
Asked if Mr Hoare had ever mentioned the recent voicemail-hacking scandal, a neighbour said: "He did say something about phone hacking. He did mention he was paranoid and that there was a conspiracy."
The neighbour said Mr Hoare had recently suffered a fall and had started to look jaundiced. Mr Hoare lived in a first-floor corner flat with his wife, Jo, whose car was in the car park of the four-storey block.
Speaking to BBC Radio 4's PM programme, Mr Hoare said phone hacking was "endemic" in the newspaper industry. Mr Hoare, who worked on The Sun before being recruited by Mr Coulson to work on NOTW, said: "He was well aware that the practice exists. To deny it is a lie, simply a lie." Mr Coulson denies the allegations.
Later, Mr Hoare was interviewed by police over the allegations he had made but would offer no comment, Keir Starmer, director of Public Prosecutions, said in December.