NEW DELHI: Unearthing one of the biggest black money rackets in the national capital post demonetisation , the Income Tax department has detected a Rs 300 crore shady bullion sale and cash deposits of over Rs six crore in junked notes by a group of traders and mill owners.Officials said the department has identified the kingpin of the entire alleged racket as one A Arora who deposited cash of at least five individuals in his bank accounts and soon transferred them through RTGS to the accounts of sugar and flour mills and bullion traders in Delhi."A total of Rs 6.72 crore cash in old notes was deposited by these dozen entities. The I-T department has mounted multiple searches on these groups which are still continuing," they said.The entities and their associates, whose names have not been revealed due to investigations still being underway, have also declared some of their black assets under the ongoing black money window of the Pradhan Mantri Garib Kalyan Yojna (PMGKY), 2016, they said.Tax sleuths who searched a flour mill based in the industrial area in Delhi found "stock difference of Rs 15 lakh" and several signed cheque books in the names of multiple entities."Summons have been issued and the department is probing the bank transactions of these entities," the officials said.The department also raided the premises of a bullion trading firm where I-T officials found that it "had sold around Rs 300 crore of bullion post demonetisation."They said the sleuths were "startled" to find that the firm was using a cryptic software called 'Hazir' to record its 'kuchha' (un-official) and 'puckka' (official) sales."The department has sent the electronic gadgets and mobilephones for forensic retrieval of data that is either hidden or erased," they added.The entire racket was being run with an attempt to convert the black money in old notes into white and a number of other people associated with this group are under the scanner of the department, the officials said, describing it as one of the biggest cases of black funds in Delhi since the November 8 announcement.Earlier, the department had found huge irregularities worth Rs 120 crore deposits in a cooperative bank based in the old Delhi area.