According to a source, the anti-graft agency had opened an investigation paper earlier this year and had interviewed several witnesses.

However, the status of the probe remains unknown.

According to the source, several NGOs had raised concerns about the alleged illegal mining, which had been carried out indiscriminately.

The source also said several witnesses had come forward to lodge a formal report with MACC, urging it to investigate the menteri besar for alleged abuse of power and graft following a letter, which had been addressed to the home ministry, that went viral on social media.

When contacted, MACC deputy chief commissioner (operations) Ahmad Khusairi Yahaya confirmed the matter.

He said the menteri besar would be called in for questioning soon. He declined to give further details.