New Delhi, Nov 25 (IANS): A special court hearing a coal block allocation case, involving industrialist Kumar Mangalam Birla, Tuesday asked the CBI why former prime minister Manmohan Singh, who held coal portfolio at that time, was not examined during the probe.

When Special Judge Bharat Parashar asked the investigating officer (IO) if officials at the Prime Minister's Office (PMO) and the then coal minister were examined, the officer said some PMO officials were examined but the then coal minister was not.

The court then asked the Central Bureau of Investigation (CBI) why the minister was not examined and did the agency not think his examination was necessary.

The IO told the court that it was found that his examination was not necessary.

He added the CBI was not granted permission to quiz him.

The court asked the CBI to bring the case diary and posted the matter for Nov 27 for hearing.

The court was hearing the closure report in a coal block allocation case involving Kumar Mangalam Birla and others which was filed last month.

In an earlier hearing, the court sought clarifications from the investigating agency whether an element of criminality was involved in allocating the coal blocks to the Birla-promoted Hindalco.

It is alleged in the FIR that during 2005, the accused people in a criminal conspiracy with one another and then public servants abused their positions and showed undue favour to an Odisha-based industry in allocation of Talabira-II and Talabira-III coal blocks along with a public sector undertaking of Tamil Nadu.

Special public prosecutor (SPP) R.S. Cheema in the last hearing told the judge that the court can take cognizance of the CBI's closure report filed Oct 21 as there was no prima facie "evidence against the accused to show their involvement".

The CBI had booked Birla, former coal secretary P.C. Parakh and others on charges of criminal conspiracy and corruption in the allocation of coal blocks in October 2013.

But it filed a closure report in the case Aug 28, saying: "The evidence collected during investigations did not substantiate the allegations levelled against the persons named in the FIR (first information report)."

The court earlier also sought to know on what basis the CBI drew its conclusion to close the case and what kind of investigation it had conducted.