Datin Seri Rosmah Mansor, wife of former Malaysian prime minister Najib Razak, has been summoned for another round of questioning at the anti-graft agency's offices today.

She is expected to be quizzed by investigators at the Malaysian Anti-Corruption Commission (MACC) headquarters in Putrajaya at 10am.

"She is being probed under section 4(1) of the Anti-Money Laundering and Anti-Terrorism Financing Act 2001 for receiving and transferring funds obtained from money-laundering activities," a source told The Straits Times yesterday. This will be her third visit to the MACC. The last one on Sept 25 lasted 13 hours.

The source said that among the issues that would be raised during the interrogation is the purchase of more than RM1 million (S$332,000) worth of hormone-based anti-ageing products from the United States.

In June, Madam Rosmah, 66, was questioned by the MACC as part of its probe into SRC International, a former subsidiary of state fund 1Malaysia Development Berhad. Investigators believe funds from SRC International may have been used to purchase the health supplements.

Her husband Najib faces 32 charges involving criminal breach of trust, money laundering and abuse of power. These include charges related to RM42 million allegedly paid by SRC International into his bank accounts.