The Central Bureau of Investigation has begun probing six more private mining and coal companies which are believed to have secured coal blocks wrongfully and by misrepresenting facts. A fresh round of first information reports is likely to be registered by month-end, government sources said.

The CBI is scrutinising the role of the six companies, some having been allotted coal blocks in Jharkhand, and also probing firms and people who were closely associated with Madhu Koda who had ruled the State with Congress support.