LUCKNOW, Sept. 15 -- Twelve contractors and five railway employees were being investigated for allegedly using counterfeit fixed deposit receipts (FDRs), experience certificates and other documents to secure railway contracts, senior Central Bureau of Investigation (CBI) officials said. An official said the CBI Lucknow unit conducted inspections at the divisional railway manager (DRM) offices in Lucknow and Varanasi four days ago. Later, the DRM office in Gorakhpur was also searched. "The CBI will conduct interrogations to gather more information after scrutinising the seized documents," he added. He said the allegations involved the submission of fake documents to secure contracts for railway projects. He said the CBI was investigating the matter to determine the extent of the irregularities and identify those involved. The railway authorities may also take disciplinary action against the employees involved. According to sources, the CBI suspects that some officials may have colluded with contractors to manipulate income certificates. In its searches, the agency seized several documents, including 10 FDRs and multiple experience certificates, it is learnt. The highest number of irregularities was in Varanasi. The CBI took action in a similar case two months ago, arresting several officials, including a deputy chief engineer and a senior section engineer, for allegedly accepting bribes in exchange for passing bills....