PUTRAJAYA (July 5): Riza Aziz has been summoned to return to the Malaysian Anti-Corruption Commission (MACC) headquarters here tomorrow (Friday) for the fourth consecutive day of questioning, after having been questioned for a little over six hours today.

Riza, stepson of former Prime Minister Datuk Seri Najib Razak, is expected to return at 10.30am tomorrow, according to an official of the anti-graft agency.

Earlier today, Riza's familiar three-vehicle convoy was seen entering the premise at 11.11am — some 40 minutes later than he was scheduled to arrive.

The same convoy was spotted heading out in the afternoon before returning an hour later, presumably for a lunch break. He eventually left the premises today at 6.40pm.

Riza has been visiting the MACC headquarters every day since Tuesday, apparently to be questioned on links between 1Malaysia Development Bhd (1MDB) and Hollywood production firm Red Granite Pictures Inc, which he co-founded.

All in, he has spent over 20 hours in the premises over the course of three days.

In March this year, Red Granite Pictures agreed to pay US$60 million to the US Justice Department to settle claims it financed Oscar-nominated film "Wolf of Wall Street" and two other movies using over US$100 million sourced from 1MDB.

Riza is also known as a friend of Jho Taek Low or Jho Low, who was central to the 1MDB graft fiasco with money trails linking the duo to different assets including classical paintings and several luxury real estate, among others.

Riza's interrogation — expected to last five days — came in the midst of Najib's arrest on Tuesday, on four charges relating to allegations of RM42 million siphoned from 1MDB's former unit SRC International Sdn Bhd.

Najib, who spent a night at the MACC lock-up on Tuesday, was charged on four counts at the High Court and subsequently granted RM1 million bail on Wednesday.