NEW DELHI: Enforcement Directorate sleuths today conducted searches at about a dozen premises spread over three states in connection with its money laundering probe against Himachal Pradesh Chief Minister Virbhadra Singh Official sources said raids were carried out in Delhi, Mumbai (Maharashtra) and Kolkata West Bengal ) on some associates of Singh and those named in the FIR registered by the agency in the national capital recently.The searches were launched early this morning, the sources said, adding that raids were also carried out on premises of some business entities that allegedly received funds from associates of Singh.ED filed the money laundering case against Singh under provisions of the Prevention of Money Laundering Act (PMLA) after taking cognisance of a criminal complaint filed by the CBI in this regard in September.The sources said investigators have gathered some "important" documents to probe and detect the "proceeds of crime" allegedly channelled by Singh and his associates by using purported illegal routes.It is alleged that Singh and his family members amassed wealth of Rs 6.1 crore between 2009 and 2011 when he was the Union Minister of Steel.CBI suspects that during the 2009-11 period, Singh allegedly invested Rs 6.1 crore in life insurance policies in his and his family members' names through LIC agent Chauhan, claiming this money to be his agricultural income.It is alleged Singh attempted to legitimise the same as agricultural income by filing revised Income-Tax returns in 2012.