Disgruntled Royal Malaysian Customs Department officers allegedly leaked information on the transit of a diamond ring worth RM24 million in 2011 to damage then prime minister Najib Abdul Razak's reputation.

This allegation was made by former Malaysian Anti-Corruption Commission (MACC) chief Abu Kassim Mohamed (above) in a speech delivered later that year and which has now made its way on video-sharing site YouTube (view video below).

During the speech, Abu Kassim said the errant officers had leaked a document known as "Borang Kastam 1" which showed the item entering the country while withholding "Borang Kastam 2" which showed the item leaving the country...