The Journal broke the news Friday that Malaysian government investigators have discovered evidence of potential corruption involving Prime Minister Najib Razak. Almost $700 million linked to the state-owned investment fund 1Malaysia Development Bhd., or 1MDB, was allegedly transferred into his personal accounts. Neither the original source or ultimate destination of the money is clear.

Mr. Najib’s office put out a statement that “there have been concerted efforts by certain individuals to undermine confidence in our economy,...