Its chief commissioner, Tan Sri Azam Baki, said that, as a result of the investigation, Mahathir's two sons were also served a notice to declare their assets within the period stipulated in the notice, under Section 36 of the MACC Act 2009.
"I don't intend to go into more detail about the case.
"Let the MACC continue the investigation first until I think of a suitable time for us to announce the findings of the investigation into the case," he said.
He said this to reporters after officiating the new MACC Gua Musang branch office, on the 1st floor of the Bangunan Persekutuan, here, today.
On Jan 18 and Jan 26, MACC reportedly served Mahathir's sons - Mirzan and Tan Sri Mokhzani respectively - with a notice to declare all movable and immovable assets under their possession, in the country and abroad, within 30 days from the date of the notice.
Mokhzani was then investigated under the MACC Act 2009 and the Anti-Money Laundering, Anti-Terrorist Financing and Proceeds of Unlawful Activities Act 2001.
Meanwhile, when asked to comment on the investigation into the case of former Prime Minister Tan Sri Muhyiddin Yassin's son-in-law, Azam said there were new indications that Datuk Seri Muhammad Adlan Berhan was somewhere shopping.
"Based on the result of MACC monitoring, he (Muhammad Adlan) has used his credit cards in several countries.
"MACC has applied to Interpol for a Red Notice on him, and we are still tracking him down to be charged in court," he said.
In August last year, MACC reportedly tracked down two men to assist in its investigation of the corruption and embezzlement case, in the registration, recruitment and biometric storage of foreign workers in a ministry.
The first individual is Muhammad Adlan, 48, with his last known address as Lot 65, Sunway Kiara Hills, Jalan 32/70A Desa Sri Hartamas, while the second individual is Mansoor Saat, 69, a lawyer, with his last known address as No.5 Jalan SS19/1C Subang Jaya, Selangor.
-- BERNAMA
