Tierney has been under fire since 2010 when his wife pleaded guilty to helping her fugitive brother manage a bank account into which funds from an illegal offshore gambling business were being funneled.
The Boston Globe reports that the Ethics Committee chairman said the evidence available now is "inconclusive" as to whether the money should be considered a gift — i.e. not taxable — or income, in which case taxes would be owed.
The scandal led to a tough election season that year against Republican Bill Hudak and an even tougher election against former Senate Minority Leader Richard Tisei in 2012, when the scandal remained in the spotlight. That year, a group of Democrats calling themselves Democrats for Tisei campaigned for Tisei.