(CNN) — Pope Francis was secretly recorded during a phone call with one of his cardinals, a Vatican financial investigation revealed Thursday.

A Vatican court heard an audio recording between Pope Francis and Cardinal Angelo Pequie, one of the defendants in the trial, in which the cardinal asks the pontiff to confirm that he has approved payment for the release of a nun kidnapped in Africa.

Journalists were not allowed to listen to the recording, but Italian news agency Adnkronos later published the financial police transcript. All three defense lawyers present at the trial later confirmed the content of the conversation to reporters present.

The recording was made by a third party who was in the room with Cardinal Pequio during the call on July 24, 2021. The phone conversation took place three days before the opening of the Vatican’s trial, which accused Pequie of corruption and abuse of office. Francisco left the hospital after the appendectomy.

In the call, Bequeau asks the pope to confirm that he authorized payments made to a self-described defense consultant named Cardinal Cecilia Marogna — accused of fraud at the trial — so she would pay the company. The British Inkerman Group aims to help win the release of a nun kidnapped by Islamist militants in Mali in 2017, the transcript said.

According to Cardinal Pesiu, then number two in the Vatican Secretariat, 350,000 euros (US$363,706) were paid to the British company and 500,000 euros (US$519,580) in ransom for the nun.

According to the transcript, the pope said he vaguely remembered the matter in the call and asked the cardinal to put in writing what the pope wanted to confirm.

Vatican law does not stipulate that a pope may be called as a witness at a trial.

Cardinal Peque, who was deposed by Pope Francis in September 2020 and stripped of most of his cardinal rights, has always maintained that any financial transaction he made must have the full approval of his superiors, including the papacy. Pesiu and Marogna pleaded not guilty to all charges at trial.

A statement sent to CNN by Becciu’s lawyers on Thursday did not comment on the secretly recorded phone call.

The revelations about a secretly recorded phone call and what Pope Francis knew about Vatican financial transactions are the latest in a long and complicated investigation into the purchase of a luxury Vatican building by 10 people accused of fraud and extortion in London.