The CBI on Tuesday began questioning the Vice President of Banking Operations of Mehul Choksi's Gitanjali Group in connection with its ongoing probe into the multi-crore PNB fraud case, officials said."Vipul Chitalia was picked up for questioning," a Central Bureau of Investigation (CBI) official in Delhi told IANS.He said Chitalia was taken away from the Mumbai airport by the CBI, soon after he landed in the city from Bangkok.Choksi, along with diamond jeweller Nirav Modi, has been accused of defrauding the Punjab National Bank of Rs 12,600 crore, including Rs 1,300 crore being added to the fraud kitty on February 26.The CBI had filed the first FIR in the scam on February 14 against Nirav Modi, his wife Ami, brother Nishal, uncle Choksi and his firms Diamond R US, Solar Exports and Stellar Diamond.Modi, his family and Choksi had left the country in early January.The CBI filed a second FIR on February 15 for a Rs 4,886.72-crore fraud against Choksi's Gitanjali Group.Till date, the Enforcement Directorate (ED) has carried out searches at over 198 locations across the country and seized properties worth nearly Rs 6,000 crore, while the CBI has arrested at least 18 persons in the case so far.