Post-mortem examinations show "no evidence" of third party involvement in the death of phone-hacking whistleblower Sean Hoare, Hertfordshire police said tonight.
Examinations on the body confirmed the death is "non-suspicious", a Hertfordshire Police spokeswoman said.
She added that it could take several weeks for toxicology test results to be released.
Neighbours of the ex-journalist, who did not want to be named, described him as "paranoid" and unwell in the weeks before his death.
One said his friend - who battled alcohol abuse - had told residents about voicemail interception long before it hit the headlines.
Last year, Mr Hoare publicly claimed that Coulson was aware of phone hacking while he was editor at the News of the World.
He gave an interview to the New York Times, and then to the BBC, about the use of phone hacking at the newspaper.
Speaking to BBC Radio 4's PM programme, he 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 the News of the World, 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, Director of Public Prosecutions Keir Starmer said in December.
The showbiz journalist was dismissed from the News of the World for drink and drug problems.
Officers have yet to confirm arrangements for an inquest to be opened.
PA