A 1974-batch IPS officer, Singh was appointed as member of the Union Public Service Commission in February 2013 and his tenure was till 2018.
After his retirement from CBI, Singh was in the news with reports of his purported association with Qureshi, who was being probed by the Income Tax department for alleged hawala funding and tax evasion.
"I have submitted my resignation a week back and am not sure whether it has been accepted as yet," Singh said on Wednesday.
It is understood that government has accepted his resignation but there was no official confirmation on it.
He said after the order of Mumbai special court, he wanted to submit his resignation as it was directly pointing fingers about his tenure as the CBI director.
Observing that the charges against Shah in the Sohrabuddin Sheikh and Tulsiram Prajapati fake encounters had a political undertone, a special Central Bureau of Investigation court in Mumbai had discharged him from the case on December 30.
"I found substance in the main contention made by the applicant [Shah]
The 62-year-old Singh also cited the stand of the government in the Supreme Court that Singh's association with Qureshi had disclosed some "astonishing" facts.
"It is unbecoming of a post he (Singh) had held. I am pained to say that this is the state of affairs of an organisation on which the court relies upon," Attorney General Mukul Rohatgi had said in the apex court without naming Singh.
"Qureshi had talked with the former CBI director almost on a day-to-day basis and also exchanged messages through Black Berry Messenger (BBM). Whatever I have said is a trailer and the real story is yet to come," Rohatgi had said in the court in October last year.
Singh and his wife had been served an Income Tax notice last year asking them to give details about their credit card transactions.
His resignation comes at a time when Enforcement Directorate is mulling registering a case against Qureshi for alleged violation of Money Laundering Act.
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