Chennai: Five days after TOI expose on the theft of 34 hard disks relating to coal purchase, transformer deals, finance, taxation and GST from the TNEB headquarters, Tamil Nadu DGP Mahesh Kumar Aggarwal transferred the investigation to CB-CID on Monday. The order is necessitated because the scope of the probe has expanded and the concerns over the nature of the data stored in the missing devices have grown.The theft came to light on May 20 after hard disks containing official data went missing from the headquarters. A complaint was lodged with the Chintadripet police, who registered a case and launched an investigation.During the inquiry, police arrested a contract employee, Gopinath, 31, of Valarpuram in Ranipet district, suspected of stealing the hard disks. Investigators found that the stolen devices were transported to Bengaluru and sold to a shop there. Police subsequently recovered 34 hard disks and arrested another person, Murali Manohar, 33, of Bengaluru, for buying the stolen hard disks from Gopinath.The investigation revealed that the theft involved more hard disks than initially reported. Police continued inquiries to determine the motive behind the theft and whether any data was accessed, copied or destroyed.The theft triggered a public outcry as the the stolen hard disks supposedly contained records related to administrative decisions, confidential tender details and purchase receipts, and other official transactions within the electricity department. Investigators are examining the nature of the data stored on the recovered devices and whether any sensitive information was compromised.With the investigation extending beyond Chennai and involving suspects in another state, the DGP ordered the transfer of the case to CB-CID. The specialised agency is expected to examine the circumstances surrounding the theft, trace all those involved, and determine whether there was any larger conspiracy behind the removal of the hard disks.