A Malaysian court on Monday rejected former Prime Minister Najib Razak’s request to serve the remainder of his graft sentence under house arrest, ruling that a rare royal order he cited was not valid under constitutional requirements.

The High Court said the house arrest was “not a valid order” as the king’s prerogative of mercy must follow the advice of the Pardons Board and cannot be issued independently. Najib’s lawyer, Muhammad Shafee Abdullah, said the former leader was disappointed and plans to appeal the verdict.

Najib, 72, is serving a six-year prison term after the Pardons Board reduced his original 12-year sentence last year. He was convicted in 2020 for abuse of power, criminal breach of trust, and money laundering over 42 million ringgit ($10.3 million) linked to SRC International, a former unit of the 1MDB state fund. He began his sentence in August 2022, becoming Malaysia’s first ex-leader to be jailed.

The court’s decision came days before a separate ruling in another graft trial, where Najib faces charges of abusing power and laundering more than $700 million from 1MDB. Conviction in that case could add decades to his sentence. Najib denies wrongdoing, claiming financier Low Taek Jho duped him; Low remains at large.

The 1MDB scandal, which investigators say involved at least $4.5 billion stolen and laundered through international accounts for luxury purchases and Hollywood films, contributed to Najib’s government losing the 2018 election after ruling Malaysia since independence. Despite his conviction, he retains influence within the United Malays National Organization, now part of Prime Minister Anwar Ibrahim’s unity government.