Mr Bini's lawyers have since referred the case to the UN's Working Group on Arbitrary Detention, which investigates arbitrary arrests and detention around the world.
His legal team claims the ongoing detention is contrary to both Ecuadorian and international law.
Mr Bini's lawyers said the prosecutor "did not do his job" by failing to identify or explain the nature of the charges.
"In the court, sweeping accusations of hacking were presented, but it has not been possible to say which computer systems are involved. We feel that he is accused of skills that he possesses and not of anything he has done," one of his lawyers, Toby Cadman, told Swedish news wire TT News Agency on Wednesday.
"What the judge said when he was in court last was astonishing. He said that Bini cannot be released because he has not been able to determine what crime he has committed or who has been subjected to it," he said.
"For us, deprivation of liberty appears to be completely unfounded."
The Swede's supporters claim his detention is only because of his friendship with Mr Assange and the case represents a broader crackdown against WikiLeaks.
"He is innocent and that is the only explanation," his father Dag Gustafsson told TT.
In May, Mr Bini published an open letter to Ecuador's President Lenín Moreno, who has called him a "hacker" that was trying to undermine the government.
"Your prosecutor says I'm being investigated for attacking the integrity of computer systems. But he doesn't say more, except that my books are suspicious. What systems did I attack? When? How? Do you even know? I don’t."
"I'm confused. Why did you do all this to me? I know... you and Mr Assange have had your differences but, is that really enough to treat me like this?"
Mr Bini wrote he had lived in Ecuador's capital Quito for five years and that he was planning to apply for permanent residency.
"Let me be clear. I have never done anything aimed to attack or destabilise your country. That’s not who I am."
Mr Bini and Mr Assange have been friends for years, with CNN reporting that Mr Bini visited Mr Assange at the Ecuadorian embassy in London at least 15 times since 2015.
The Swede told CNN, "just as me, he believes very strongly in the right to privacy".
"So the first time I went, I actually went to talk to him about these kinds of things. I kept coming back because I like him, because he is a friend of mine and I kept coming back because more and more people abandoned him," he told the network.
"I felt it was my responsibility to do it but also my pleasure as a friend."
Mr Assange was taken into British custody and sentenced to 50 weeks in prison for violating the conditions of his bail in 2012, when he sought asylum at the embassy in London.
He was later charged under US anti-espionage laws for the 2010 publication of thousands of military and diplomatic documents by WikiLeaks.
The Australian also faces a European arrest warrant against him for an alleged rape committed in Sweden the same year.
Additional reporting: AFP