Expressing unhappiness over the "prolonged delay" in the investigation of coal scam-related cases by the Central Bureau of Investigation (CBI), the Supreme Court on Monday said, “it could not be an unending affair.”

"Something has to be done. It can't go on like this," said a bench of Justice Madan B Lokur, Justice Kurian Joseph and Justice A K Sikri reminding the investigating agency that it was supposed to wrap up all the investigations by December 31, 2014 and that now 2015 is going to end.

Noting that a "considerable time has already been taken", the court granted the CBI time till March 31, 2016 and asked it to complete the investigation as early as possible.

The court observation came after the investigating agency sought its nod for relieving one of its senior officers, who is supervising investigations into coal scam-related cases, upon his "prestigious" appointment to the National Defence College.

The court said that such movement of officers from the investigating agency delays the investigation after CBI’s counsel Amarendra Sharan tried to impress upon the court that movement of the senior ranking officer for another posting may not affect the pace of investigations.

"It can't go on like this. We are very clear about it. You have to be clear as well," the court the CBI.

Sharan said the investigation was not into the old cases but in the 15 new cases that were taken up later, adding the probe into these case was "very fast".

Meanwhile, the bench was also unhappy with the Directorate of Enforcement’s provisional orders for the attachments of properties worth Rs186 crore, Rs 24.5 crore and Rs 2 crore but no complaint has been filed so far in two cases wherein the investigating agency in its progress report till September 11 had said that it would be filing "complaint shortly".

In the third case also it failed to file the complaint.

Sharan told the court that in the first two cases, the complaints was with the special public prosecutor R S Cheema who is heading the prosecution of the coal scam cases by the CBI. He also sought time till end of this month to file a fresh status report.