PARLIAMENT Police have opened three investigation papers on Dr Mahathir Mohamad for criminal defamation.

The probes under Section 500 of the Penal Code follow two police reports in Klang and one in Jinjang against the former premier.

Home Minister Ahmad Zahid Hamidi said the report in Jinjang has already been submitted to the Attorney-General's Chambers.

"The investigation paper had been referred to the AGC on Oct 9 for further instructions.

"(The other two reports) will be referred to the deputy public prosecutor for review and further instructions after the investigation is complete," he said in a written parliamentary reply.

Zahid ( photo ) was responding to a query from Tan Kok Wai (DAP-Cheras) on the outcome of police investigations on Mahathir following his increasingly aggressive efforts to oust Prime Minister Najib Abdul Razak.

Najib has refused to budge, despite the incessant attacks, and analysts have said that Mahathir is powerless to defeat Najib.

Inspector-general of police Khalid Abu Bakar previously said Mahathir was being investigated for criminal defamation for accusing Umno of corruption during the Bersih 4 rally.

However, police have yet to question Mahathir, and Khalid said there was no rush to do so.