The checking of the currency chests began on Saturday and continued on Sunday.

Among the 628 currency chests, 62 are in districts that are along Indo-Nepal border. "They are being checked on a priority basis," a senior RBI officer said. From all indications so far, it appears that the problem is confined to Dumariyaganj, the RBI officer said. The vaults of the12 banks that drew currency from Dumariyaganj have been checked and no fake currency notes were found, he added.

After fake currency notes were recovered from the chest of a SBI branch in Dumariyaganj, the UP Police had requested the RBI to check all currency chests in the state, particularly those in the districts along the Nepal border. The cashier of the Dumariyaganj SBI branch, Sudhakar Tripathi, was arrested after his name cropped up during investigations of the fake currency note seizure.

The RBI believes that the fake currency had been placed in the Dumariyaganj chest in the last eight months or so. The RBI, and also the Special Investigating Team of the UP Police which is investigating the case, are sure that the replacement of genuine currency with fake could not have been done by Tripathi without the connivance or negligence of other officers.

An official explained that the branch cashier and a manager-rank officer are supposed to operate the chest as joint custodians. Each of them keeps a key and the chest is opened only when both keys are applied simultaneously. A cash coolie accompanies the custodians to carry the currency, he revealed.