Investigators from both the House Ways and Means and House Oversight committees will be interviewing two front-line IRS workers from the Cincinnati office in Washington DC this week, and another two next week, according to congressional sources who spoke to CNN today.

House investigators are interviewing two front-line Internal Revenue Service employees from the Cincinnati tax exempt office this week in Washington, and plan to interview two others next week, two congressional sources familiar with the investigation tell CNN.

House investigators are hoping these IRS employees will shed light on exactly why tea party and other conservative groups were inappropriately targeted for excess scrutiny when applying for tax exempt status.

This is an important development as Congressional committee members continue to try to determine whether or not any of the direction of front-line employees was politically motivated or connected to higher levels of the administration in Washington DC.

This news comes as 76% of registered voters in a Quinnipiac University Poll believe that a special prosecutor is needed to investigate the actions of the IRS in its targeting of conservative groups.