The court ordered the government to conduct a judicial inquiry into Shireen Mazari's arrest, while directing the authorities to release her.
The former human rights minister has claimed that her phone that was confiscated by the police at the time of her arrest has still not been returned to her.
Chief Justice Athar Minallah said that the former minister's arrest was apparently illegal. It was also a violation of the court order that no lawmaker could be arrested without informing the speaker, he said.
"There is a law and the Constitution. Such incidents take place when the law is not followed," the judge remarked.
When Shireen Mazari told the court that her phone has still not been returned to her, the judge ordered the authorities to give her phone back.
While talking to media, she held Interior Minister Rana Sanaullah responsible for her arrest. She also said that Prime Minister Shehbaz Sharif was behind the arrest. The former minister also claimed to have been tortured by police officials while being taken into custody.
Following her arrest, Shireen Mazari's daughter Advocate Imaan Mazari filed a petition before the Islamabad High Court, after which the court ordered the authorities to produce her by 11.30 PM. The court gave these instructions despite having been closed for the day.