Najib filed a lawsuit against Mohd Rafizi Ramli, vice-president of the Keadilan Rakyat Party (PKR), for alleged slander after commenting that the prime minister and his wife, Rosmah Mansor, manipulated fuel subsidies for personal gains last November.

The prime minister also sued Chan Chee Kong, from MR multimedia, for echoing Rafizi's accusations in KPK on Facebook and Youtube.

For his part, the couple's lawyer, Hafarizam Harun, told reporters that his defendants are suing for being treated like thieves in public and demand apologies and retractions.

Meanwhile, the president of the Anti-corruption Commission of Malaysia, Abu Kassim Mohamed, said the agency
is not afraid of investigating whoever, including the Prime Minister and his wife, when referring to stories on the purchase of diamonds valued at $8 million US dollars.

These recent lawsuits coincide with strong criticism of Najib by ex Prime Minister Mahatir Mohamed regarding a state-run investments company which left millions in losses to the State and the fraudulent purchase of a submarine.