Former chief justice of Pakistan Mian Saqib Nisar on Monday issued a rebuttal — his second in as many weeks — saying that the voice in a leaked audio clip, purportedly of a conversation between him and an unidentified man regarding PML-N leaders Nawaz Sharif and Maryam Nawaz's trial, was not his.

Speaking to Dawn.com, Nisar termed the audio clip "fabricated", adding: "I have never spoken to the person in the audio call."

In the audio clip, which has not been independently verified by Dawn.com, a voice, allegedly of the former chief justice, can be heard saying: "Let me be a little blunt about it. Unfortunately, here it is the institutions that dictate judgements. In this case, we will have to punish Mian sahab (Nawaz Sharif). [I] have been told 'we have to bring Khan sahab (Imran Khan) [into power].'"

He allegedly goes on to add, "Punishment will have to be given."

When the man on the other end of the line says that Nawaz's daughter Maryam Nawaz "doesn't merit a sentence", Nisar purportedly tells him: "You are absolutely correct.

"I talked to my friends that something should be done about this but they did not agree. The independence of the judiciary will not remain. So, let it be."

Forensic analysis

According to the Fact Focus website which broke the story, the audio clip was examined by a leading firm in the United States which specialises in multimedia forensics.

"Garret Discovery has a team of leading experts who have a long experience of analysing and presenting evidence and testifying before courts in the US. The firm's analysis report certifies the integrity of the audio file and states that 'this audio has not been edited in any way,'" according to the Fact Focus report.

The Fact Focus report quotes Nisar as saying that he had never contacted any judge of an accountability court to order them to announce a verdict against Nawaz or Maryam.

"Why I would do that?" Nisar asked, according to the report. "I have no grudges against Mian Nawaz Sharif."

The former chief justice said that no one from the Pakistan Army or the Inter-Services Intelligence (ISI) had ever contacted him or pressured him regarding the case, the report stated.

PML-N calls for explanation

Meanwhile, PML-N leaders renewed their criticism of Nisar over the alleged audio clip, calling on the former chief justice to explain his position.

Party president Shehbaz Sharif claimed the audio clip showed how Nawaz and Maryam were "targeted as part of a grand scheme to keep them out of political process".

"Time has come to right the wrongs inflicted on them. The nation looks forward to justice system," he tweeted.

PML-N spokesperson Marriyum Aurangzeb shared the screenshots of the forensic report included in the Fact Focus story, commenting: "The report card is present."

Terming the alleged audio clip "serious stuff", secretary general Ahsan Iqbal called on Nisar to explain his position.

"These tapes provide evidence to what was an open secret in Islamabad."

"The one who is refusing to recognise his voice today will reject his written judgements too tomorrow," said former senator Pervaiz Rashid.

Questioning the veracity of the audio clip and implying that such clips can be created, Information Minister Fawad Chaudhry shared another audio in which a voice strikingly similar to Nawaz's can be heard bizarrely criticising himself.

"What [things] have technology made possible. One example is this," he tweeted along with the clip.

Leaked audio clip follows last week's affidavit controversy

This is the second time in as many weeks that the former chief justice has made headlines. Last Monday, Nisar had rubbished allegations levelled against him by former top judge of Gilgit-Baltistan, Rana Shamim, regarding a collusion to deny bails to Nawaz and Maryam before general elections 2018.

An investigative report published in The News by journalist Ansar Abbasi on the same day had quoted Shamim as saying in an alleged affidavit that he witnessed Nisar relaying instructions to a high court judge to not release the the father-daughter duo in the corruption references against them.

The document being quoted by The News report has been notarised by Charles D. Guthrie, a London-based solicitor.

According to the alleged affidavit, Shamim claims the ex-CJP had travelled to GB for vacations in 2018 and on one occasion appeared "very disturbed" while speaking to his registrar on the phone, asking him to get in touch with a high court judge.

Shamim said that Nisar was finally able to get in touch with the judge and told him that Nawaz and Maryam must remain in jail until elections are over, after which "he became calm and happily demanded another cup of tea".

According to the document, Shamim said he told Nisar that Nawaz had been falsely implicated, to which the former CJP replied: "Rana sahab the chemistry of Punjab is different from GB."

Speaking to Dawn.com, the former chief justice had vehemently denied the allegations levelled against him and called the report a "self-motivated story".

"I have never spoken to anybody or any high court judge in connection to any matter related to Mian sahab," he said.

Following the publication of the report, PML-N leaders had called for individuals involved in the matter to be brought to justice.

PML-N leader Shahid Khaqan Abbasi had demanded that a suo motu notice be taken of the matter and questioned: "If Mian Nawaz Sharif can go to jail, why can't Mian Saqib Nisar?"