Malaysia’s disgraced former prime minister Najib Razak, who is to be charged in court on Wednesday in connection with the multibillion-dollar financial scandal at the 1MDB state fund he helped set up, is facing the prospect of a lengthy jail term.

Najib’s arrest by anti-corruption investigators on Tuesday afternoon is the most dramatic development yet in the ongoing probe into the fund ordered by Prime Minister Mahathir Mohamad soon after the May 9 general election.

Najib Razak’s 1MDB chickens come home to roost

Najib’s arrest comes three years to the day after an investigation by The Wall Street Journal revealed some US$700 million of 1MDB funds had flowed to Najib’s personal accounts.

A task force Mahathir set up to investigate the scandal said in a brief statement that Najib was to be charged on Wednesday in relation to allegations involving SRC International Sdn Bhd, a former 1MDB unit.

It did not state what the charges were or if there would be subsequent arrests. The national news agency Bernama said Najib could face 10 counts of committing criminal breach of trust, which carry a maximum punishment of 20 years each.

Najib’s wife Rosmah Mansor, stepson Riza Aziz and Ahmad Zahid Hamidi, his former deputy prime minister, are among the high profile figures who have been quizzed by investigators.

Arrested in his bungalow in a lush, suburban district near Kuala Lumpur, Najib has been transferred to a holding cell in the headquarters of the Malaysian Anti-Corruption Commission (MACC) in the administrative capital of Putrajaya to await Wednesday’s arraignment.

Rosmah Mansor: from Malaysia’s ‘first lady’ to ‘bag lady’

There were no public images of him being arrested.

The local news website The Malaysian Insight said the former leader had been taken to the MACC offices in a convoy of unmarked police cars.

There was no immediate comment from Najib’s lawyers or spokesman, but the 65-year-old in two media interviews in June strenuously denied any wrongdoing.

Instead, he insisted that Mahathir, his 92-year-old one-time mentor, was waging a campaign of “political revenge” against him after the general election.

Mahathir, prime minister from 1981 to 2003, crossed aisles to join opposition forces he once assailed to remove Najib from power following the 1MDB revelations in 2015.

Najib at the time removed his then attorney general Abdul Gani Patail and several ministers after they questioned him over the corruption allegations.

1MDB case must be watertight, says Malaysia’s Mahathir

In the recent interviews, Najib distanced himself from allegations that some US$4.5 billion was misappropriated from 1MDB, and instead pinned the blame for possible wrongdoing on the fund’s board. He was the chairman of the fund’s advisory board from 2009 to 2016.

He reiterated his long-standing position that the funds in his personal account were political donations from a Saudi monarch.

Asked about the huge haul of jewellery, watches and cash amounting to US$273 million that police seized during raids of his properties, Najib said most of the items were gifts.

The cash, he said, was political donations to the United Malays National Organisation he helmed and which had ruled Malaysia uninterrupted for six decades until the May 9 polls.

Mahathir and his top lieutenants believe investigators will be able to show incontrovertible evidence that these assertions are untrue and that Najib plundered 1MDB for personal gain.

In an interview with the South China Morning Post in June, Mahathir said he expected investigators to gather evidence “that cannot be disputed”.

Gathered evidence will ensure “judges won’t base their judgment on sentiment [but] they base judgment on facts and evidence,” Mahathir said.

Apart from the 1MDB case, Najib could be ensnared by the reopening last month of an investigation into the 2006 murder of Mongolian model Altantuya Shaariibuu by two former members of his personal security detail.

Najib denies any involvement but the question of who ordered the killing remains unanswered.

Meanwhile, some of the embattled leader’s harshest critics on Tuesday urged authorities to treat the former leader with dignity.

Among them were close allies of Anwar Ibrahim, the reformist icon who was twice jailed for sodomy charges he believes were trumped up – including once during Najib’s era.

During Najib’s nine years in power, international rights groups regularly accused the leader of arbitrarily detaining and charging political opponents with dubious offences.

“I was among his fiercest critics. But I pray that he is accorded kindness and treated with dignity befitting a former PM,” said Rafizi Ramli, a lieutenant of Anwar.