Taiwanese prosecutors on Friday questioned relatives of former president Chen Shui-bian over a corruption scandal, two days after the ex-leader was detained in an ongoing money laundering probe.

Chen`s son Chen Chih-chung and daughter-in-law Huang Jui-ching, both defendants in the case, arrived at the prosecutor`s office early Friday amid speculation they would also be formally detained.

The pair were being questioned over the alleged transfer of 21 million US dollars to Swiss bank accounts belonging to Chen`s daughter-in-law in 2007. The funds have since been frozen.

The couple have said they were not aware of the source of the funds.

Prosecutors also summoned Chen`s daughter, Chen Hsing-yu, as a witness, but granted her request to appear at a later date.

A court ordered former president Chen locked up Wednesday after 24 hours of high drama that saw him led away in handcuffs, taken to hospital after saying he had been beaten by police, and then finally put behind bars.

Chen has not eaten since being detained, in protest at what he insists is a politically-motivated investigation, according to his lawyer.

Chen, the first former Taiwanese leader to be arrested, faces allegations of embezzling around 15 million Taiwan dollars (about 450,000 US) while in office.

He could be detained for up to four months before prosecutors have to charge him.

His detention is the latest development in a long-running corruption probe against the former leader. He has admitted submitting falsified expense forms while in office but said the money was used for `secret diplomatic missions.`

He has denied personally benefitting from the falsified expenses.

Chen has also admitted his wife wired 20 million US dollars abroad from past campaign funds but has denied laundering money.

Chen, whose pro-independence stance in office set him against Beijing, has repeatedly accused the island`s China-friendly government of being behind the allegations of embezzlement, money laundering, taking bribes and forgery.