The ASG informed the court that the money laundering probe in the 2G case and the Aircel-Maxis case are already over.
The bench, however, did not allow the submissions of the central government and said that the officers had the trust of the apex court and cannot be treated like this.
Earlier the apex court had said that it will pass an appropriate order after hearing Singh as to whether he wants to continue with the ED or not.
Raising the issue of Singh, BJP leader Subramanium Swamy had said that despite the apex court's May 1 order he had not been reinstated into the investigation and it was not known "what powerful element are working" that he is out of the probe.
Singh had sought to recuse himself from the investigation as attempts were being made to destroy the case.
Swamy was one of the petitioners on whose plea the 2G licences were scrapped by the apex court which is monitoring the probe by the CBI and the ED.
Senior advocate K K Venugopal, while appearing for the ED, had placed before the bench a note in which Singh had expressed his desire to go on study leave.
The bench after perusing the copy of his letter, written to ED in which he said he would be available for the probe whenever required, had said since it concerns an officer it would like to hear him.
It was reported that Singh had taken a year-long 'study leave' apparently owing to lack of clarity over his continuance in the agency.
The apex court on May 1 had ordered that Singh be not taken away from the ongoing probe in 2G cases and directed that he will continue with the investigation till completion of trial.
The order was passed after it was alleged that Singh was being transferred to his parent cadre in Uttar Pradesh.