A mystery company that pumped $1 million into a political committee backing Mitt Romney has been dissolved just months after it was formed, leaving few clues as to who was behind one of the biggest contributions yet of the 2012 presidential campaign.

The company, W Spann LLC, was formed in March by a Boston lawyer who specializes in estate tax planning for "high net worth individuals," according to corporate records and the lawyer’s bio on her firm’s website.

The corporate records provide no information about the owner of the firm, its address or its type of business.

Six weeks later, W Spann LLC made its million-dollar donation to Restore Our Future - a new so-called "super PAC" started by a group of former Romney political aides to boost the former Massachusetts governor's presidential bid. It listed its address as being in a midtown Manhattan office building that has no record of such a tenant.