New Delhi/ Bhopal, June 24 (ANI): Madhya Pradesh Chief Minister Shivraj Singh Chouhan on Tuesday filed a defamation case against Congress leader KK Mishra, who has levelled charges against the Madhya Pradesh CM in the multi-crore Vyapam Scam. The recruitment scam had reportedly involved manipulation in the selection process for government jobs conducted by the Madhya Pradesh Professional Examination Board (MPPEB). A Special Task Force has been constituted for an investigation into the Vyapam scam which had detained Laxmikant Sharma, a former state technical education minister, for interrogation. The high profile teacher's recruitment scam in Madhya Pradesh is being linked to Chief Minister Shivraj Singh Chouhan's wife, Sadhna Singh.