Today, The CBI filed the fourth chargesheet in the continuing probe into the post-poll violence instances in West Bengal . The chargesheet was filed at Krishnanagar court docket in Nadia district in reference to the killing of a BJP employee allegedly by Trinamool Congress members .The Calcutta High Court last month directed the CBI to probe the post-poll violence cases. So far, the CBI has filed 34 FIRs in connection with murders and other heinous crimes perpetrated after the election results were announced.