In what could lead to problems for petroleum ministry officials who handled the KG Basin matter, the CBI has sent a letter to the ministry seeking clarification on "steps taken by it to recover the penalty from Reliance Industries Limited (RIL) for unfinished work". CBI sources said the letter was sent a few days ago as there were several complications about penalty amount, which is also part of the probe. The sources added that they were in the final stages of deciding about registering FIRs.