Former deputy governor Aulia Pohan, whose daughter is married to Dr Yudhoyono's eldest son, was accused of approving 100 billion rupiah (S$12.4 million) in illegal payments to Members of Parliament and former colleagues at the central bank.

It is the first time a relative of an incumbent Indonesian president has been detained.

Three other former deputy central bank governors who collectively approved the controversial payments in 2003 were also detained yesterday.

The suspects were accused of giving bribes amounting to 31.5 billion rupiah to lawmakers who were deliberating a new central bank law in 2003.

Around 68.5 billion rupiah was said to have been spent to help finance legal fees of former central bank senior officials who had been accused of embezzling billions of dollars of liquidity funds that went missing during the 1997/1998 Asian financial crisis.

Last month, the former governor of Indonesia's central bank was sentenced to five years in jail for his role in the same case.

Burhanuddin Abdullah, 60, whose term as Bank Indonesia governor ended in May this year, told the court he would appeal.

Burhanuddin had supported commitments made by his predecessor and colleagues, who include Mr Aulia, the anti-corruption court ruled last month.

Indonesia's anti-graft agency, KPK, has in recent months stepped up investigations of many state agencies and ministries, detaining officials from the central bank, the Attorney-General's office, Parliament and the Customs department.

Set up in 2003 by an Act of Parliament, the KPK is an independent body with broad powers aimed at eradicating corruption, and which answers to the House of Representatives.

When asked if he was ready to stay in a prison cell, Mr Aulia replied on his way out of the anti- corruption commission's building: 'How can I say I'm not?'

He was later transported to a police detention facility in Kelapa Dua, outside Jakarta.

Mr Aulia, 63, has denied any wrongdoing.

He will remain in detention until the anti-graft agency wraps up its investigation and submits the case to the anti-corruption court.

The KPK can keep him under detention for 20 days before taking the case to the anti-corruption court, his lawyer Amir Karyatin told Bloomberg.

Another lawyer on Mr Aulia's team of lawyers, Mr Syafardi, yesterday questioned the need to detain Mr Aulia because the client had been cooperative throughout the investigation.

Mr Maswardi Rauf, a senior political science lecturer at the University of Indonesia in Jakarta, said that the development would help boost Dr Yudhoyono's political standing.

'It is saddening for SBY. But on the same token, this would give a positive light to his political standing,' he told The Straits Times, referring to Dr Yudhoyono by his popular nickname SBY.

'For SBY, it's a sacrifice that he's refraining from intervening and letting the law work impartially.'

Dr Yudhoyono is seeking a second five-year term in next year's general election.

wahyudis@sph.com.sg