Sen. Mary Landrieu (D-La.) and Rep. Bill Cassidy (R-La.) were absent ahead of Saturday's vote.
Americans for Prosperity's Senate runoff ad invokes the controversial ObamaCare adviser.
His wife asked supporters in an email Tuesday to donate to his campaign.
Cassidy pressed Landrieu over whether she agreed with the controversial ObamaCare consultant.
Sen. Landrieu accused Rep. Cassidy of “padding his pockets” at the expense of taxpayers.
Probe comes amid Dem allegations he wrongly billed the school for work while in Congress.
The Landrieu campaign calls Cassidy a “fraud” who is “caught up in lies."
Republicans voting early in the runoff increased, bringing good news for Rep. Bill Cassidy.
Sen. Mary Landrieu wants her challenger to bring 63 months of records to Monday's debate.
Cassidy (R) outraised Sen. Landrieu (D) by $500,000 in last month and has more in the bank.