The Enforcement Directorate yesterday questioned Himachal Pradesh Chief Minister Virbhadra Singh's wife Pratibha Singh in connection with an alleged money laundering case. <br/><br/>The agency had earlier issued summons to her to appear before the Investigating Officer of the case. <br/><br/>Earlier, the Directorate had attached assets worth eight crore rupees of the Chief Minister. It is probing allegations against Mr. Singh and others of having amassing Rs 6.1 crore of disproportionate assets when he was Union Steel Minister during UPA rule. <br/><br/>The ED had filed a case under criminal provisions of money laundering laws after taking cognisance of a complaint filed by the CBI in this regard in September last year.