The CBI on Wednesday registered 18 cases related to land allotment to private firms, including those associated with Congress chief Sonia Gandhis son-in-law Robert Vadra, in connection with the probe into alleged land scams in Bikaner in Rajasthan. Informed sources said four of the 18 FIRs are against Vadra's company, which was said to be involved in illegal purchase of nearly 275 bighas (more than 100 acres) of land. All the FIRs are in connection with the purchase of close to 1,400 bighas (approx 550 acres) in fictitious names, the sources said. The central agency's move came a week after the Rajasthan government wrote for a probe. The Central Bureau of Investigation (CBI) registered the 18 FIRS on charges of cheating, dishonestly breaking open receptacle containing property, and forgery under the Indian Penal Code on Rajasthan government's request and subsequent central notification, an official said. The CBI also took over investigation into 16 FIRs earlier registered by the Rajasthan Police. "The cases are related to alleged fraudulent and fictitious claims and allotments in lieu of land acquired for Mahajan Field Firing Range in Bikaner used by the Indian Army," CBI Spokesperson Abhishek Dayal said.