Graft investigators are in the dark over claims that one of Dr Mahathir Mohamad's aides had collected RM10 million from former prime minister Najib Abdul Razak prior to the 13th general election back in 2013.

Quoting a 'top-level source', The Star Online reported that the investigators had received no report on the matter "for now".

Even so, the source said: "There is no law to prevent one from receiving funds for political purposes."

Malaysiakini is contacting the MACC for elaboration.

The matter came to light when Najib had claimed, during an interview with Malaysiakini, that "a trusted aide" of Mahathir had collected the cash from him for use in the 13th general election (GE13).

He said this when asked to explain how it came that RM116 million in cash were found by police during raids on several properties linked to him and his family after last month's GE14.

Najib had replied that while not widely known, collecting donations and cash for use during elections was a common practice as running an election campaign is an "expensive affair".

Asked about this claim by Najib, Mahathir merely told his predecessor to "show evidence".

Najib has also declared that most of the other valuables seized from the properties, most in the form of luxury handbags, watches and jewellery, were "gifts" from friends and foreign dignitaries, including the RM3.5 million Rolex watch.