Swedish prosecutors have dropped a preliminary investigation into an alleged rape by Julian Assange.
It comes as his defence team launches a bid to quash his detention on the grounds he was illegally spied on.
On Tuesday Sweden's prosecution authority said even though prosecutors found the woman's claim "credible" it had taken the decision to discontinue the case.
Deputy director of public prosecutions Eva-Marie Persson said: "My assessment is that all investigative measures that can be taken have been taken. But... the evidence is not strong enough to file an indictment."
It had been investigating a 2010 rape allegation against the WikiLeaks founder that allegedly took place after a Swedish woman met the Australian at a conference in Stockholm.
Assange has always denied the allegation.
The 48-year-old has been held at a top-security British prison since April after police arrested him at the Ecuadoran embassy in London, where he had been seeking asylum since 2012 to avoid an extradition order to Sweden.
Assange was subsequently sentenced to 50 weeks in prison for breaching bail conditions when he took refuge in the embassy.
He has completed his sentence but remains in prison while his extradition case continues.
Assange’s team claim he was placed under surveillance for the duration of his time in the embassy.
They allege security firm UC Global was recruited by the Ecuadorian government.
One of his lawyers, Aitor Martinez told La Repubblica: "Over the years Mr Assange and his defence team held legal meetings inside the embassy. Those meetings were protected by the lawyer-client relationship and the fundamental right to defence.
"However we can see those meetings were spied on, according to the videos published by different media . Under these conditions, it is clear that extradition must be denied. We hope that British justice understands the scope of what has happened and denies extradition as soon as possible".
It was following his arrest that Swedish authorities reopened their 2010 rape investigation.
It had been closed in 2017 on the grounds that it was not possible to proceed with the investigation as Assange could not be reached.
In September, prosecutors said they had interviewed seven witnesses over the summer and that Assange was suspected of rape.
Ms Persson had said the material from the interviews was to be analysed further before she decided on how to proceed.
Assange is currently also the subject of a US extradition request to face charges relating to obtaining and disseminating classified information over the publishing of military documents and diplomatic cables through the WikiLeaks website.
Since his April arrest, questions regarding Assange's health have been raised, with him appearing frail and confused at court hearings.
Earlier this month, John Shipton, Assange's father warned that his son "may die in jail".
His comments followed a warning from the UN's Special Rapporteur on Torture, Nils Melzer, who said that the treatment of Assange was putting his life "at risk".
Swedish judge Nils Petter Ekdahl had said the prosecution has a duty to try and bring a suspect to justice if the evidence warrants it.
"If you believe there is enough evidence for a conviction, even in an old case, the principal rule is to charge the person," Mr Ekdahl said.
However, he said there can be exceptions to this rule if the sentence would probably be lenient owing to Assange's poor health.
The full extradition hearing is due to be heard in February 2020 after a London judge rejected a request to delay proceedings by three months.
Assange is facing 18 counts in the US including conspiring with former intelligence analyst Chelsea Manning to hack classified government computers.
He then used WikiLeaks to publish highly sensitive and classified US intelligence in 2010.
Former UK interior minister Sajid Javid signed off an order in June to allow Assange to be extradited to the US where he could spend decades in prison if convicted.
