One of India's richest men, Anil Ambani, appeared in court yesterday to answer questions about his company's role in the allegedly fraudulent allocation of telecom licences in 2008.
The tycoon, who heads Reliance ADA Group, lost a bid to postpone his appearance and answered questions from the witness stand.
Three of his Reliance Telecom executives have been charged in the case, one of the biggest corruption scandals in India's history, but Mr Ambani himself was called as a prosecution witness.
Asked about various meetings and links between his company and others accused of wrongdoing, he replied frequently that he did "not recall" or "was not aware".
Prosecutors allege that the then-telecom minister A Raja, who is also on trial, sold telecom licences in 2008 at giveaway prices to favoured companies that paid bribes to secure second-generation (2G) bandwidth.
The national auditor calculated that the losses to the state were as high as 1.766 trillion rupees (Dh99 billion at current rates), but this figure is disputed by the government and some analysts.
Three telecom companies - Reliance Telecom, Unitech Wireless and Swan - have been charged with corruption, as well as more than a dozen individuals.
They have pleaded not guilty.
Mr Ambani was asked about links between Reliance and Swan, which prosecutors allege was a front for his business.
"I am not aware," he responded when asked if Reliance had invested in Swan.
When asked about the minutes of meetings at which he was allegedly present to discuss Swan's finances, he replied: "I attend a large number of meetings, I don't recall [each one]."
The small courtroom was packed with lawyers and media, with most of them forced to stand.
Mr Ambani's wife, Tina, has been summoned to give evidence today.
The so-called "2G scam" has been immensely damaging for the ruling coalition led by the Congress party, which has been ensnared in a series of corruption scandals since its re-election in 2009.