Arunga was released after the prosecution tabled court documents showing her testimony implicating her husband Quincy Timberlake for their son’s death.
She was granted bail and will return to court on October 20.
Her bail conditions include that she surrenders her passport, report to police twice a week, not be closer than 500 metres to an airport and have no contact with her husband.
Australian news site Brisbane Times quoted the testimony in which Arunga told the prosecution how her husband allegedly punched their son in the stomach before he tossed him against the wall to rid him of demons.
Timberlake remains in custody after facing murder charges while Esther is charged with accessory after the fact to murder.
Court documents reveal Timberlake admitted himself to Brisbane’s Prince Charles Mental Health hospital on July 3. A week later he was made an involuntary patient.
Four days later, Arunga told officers her husband was pushing on the boy’s stomach repeatedly because he believed he had been possessed by aliens and demons.
She said her husband “was speaking as if he was attempting to save [Sinclair] from alien embryos implanted in his stomach”, according to police documents tendered in court.
“She then observed the father of the deceased punch the deceased in the stomach with his fist,” the documents said.
Police said Sinclair’s initial post mortem results were not consistent with a fall down the stairs.
He had suffered internal injuries, bruising to his arms and torso. He also had a number of other injuries which Arunga said were caused by traditional Kenyan healing techniques prior to June 18.
Outside court, Arunga’s lawyer Chris Ford said his client was struggling with the stress of losing a child.
The pair said they were forced to flee to Australia after being allegedly being persecuted in their home country.
Last week, Timberlake’s lawyers said their client was a “loving father” and that the boy’s death was “tragic”.
“There is of course more to this tragedy than can presently be disclosed and we would caution against any prejudgment of this case,” the lawyers said in a statement.
Police only laid charges against Timberlake last week, before Arunga was arrested on Thursday. They both intend to fight their respective charges.