A 1987-batch IPS, N Dilip Singh had served in CBI for seven years before his posting in Arunachal Pradesh. After being transferred to Delhi, he served in the provision and logistic wing of Delhi Police before being posted at the ACB on September 6, 2007.

Since he moved to ACB, the unit has arrested more than 113 government officials in corruption cases over the past two years.

Singh had been making ripples in the corridors of power with sting operations that netted several senior bureaucrats, police officers and engineers in corruption cases. Among his major catches were Inspector K G Tyagi, one of Delhi Police’s ace officers who had won many awards. Tyagi was caught allegedly negotiating a bribe of Rs 26 lakh from the relatives of a murder accused.

Singh was also responsible for the swoop on NDMC officials in which 16 persons were arrested for allegedly taking bribes from shopkeepers. He also unearthed the de-silting scam in MCD.

When contacted by Newsline on Wednesday, Ranjan Mukerjee, Officer on Special Duty at the L-G office, said, “I am not aware of any such letter (issued by the chief minister).”

Chief Minister Sheila Dikshit also denied issuing such a letter.