"We find that the country's finances, for example, was abused in a way that now we are facing trouble settling debts that have risen to a trillion ringgit", he said.
In a statement today, the 1MDB's special team said the first meeting was held at the Malaysian Anti-Corruption Commission Headquarters (MACC) here today with former attorney-general Tan Sri Abdul Gani Patail, former MACC chief Tan Sri Abu Kassim Mohamed, current MACC chief commissioner Datuk Seri Mohd Shukri Abdull and former Special Branch deputy director Datuk Abdul Hamid Bador.
He was appointed head of the commission after Malaysia's new prime minister, Mahathir Mohamad, beat Najib at the polls almost two weeks ago. The new government has reopened an investigation into the case, with police raiding Najib's properties and seizing more than 300 expensive handbags as well as suitcases filled with cash, jewelry and other valuables.
The former leader has repeatedly denied any wrongdoing.
Najib was asked to explain the alleged transfer of $681m from SRC International, a subsidiary of the 1MDB fund, into his personal bank account.
Najib's lawyer, Harpal Singh Grewal, told reporters waiting outside the house that the former prime minister and his family were "really very unhappy" that police had confiscated clothes and shoes belonging to his children.More news: Warriors list Iguodala as doubtful for Game 4
Mahathir also announced a renewed effort in investigating the 1MDB scandal.
"The government hopes the setting up of this task force, comprising a multi-agency enforcement unit, will help restore the dignity of Malaysia that has been tainted by the 1MDB kleptocracy scandal", said Mahathir's office.
USA investigators say Razak's associates stole and laundered $4.5 billion from the fund, some of which also landed in Razak's bank account, and that some $23 million was used to buy a rare diamond pink necklace for Mansor.
She is reportedly to have spent $400,000 on anti-ageing products imported from the United States, including 1590 bottles of growth hormone capsules.
The previous evening, Mahathir met Xavier Justo, a Swiss national who was the first whistleblower in the 1MDB affair.
It was documents leaked by Justo, a former director of energy group PetroSaudi International, which ran an energy joint venture with 1MDB from 2009 to 2012, that triggered investigations in at least six countries. He was freed in an amnesty in 2016.