As the pressure builds ahead of the next contest in the primary fight, ABC News recently obtained an audio recording of what sounds like intensive message polling conducted on Clinton's behalf to a caller in the northern part of the state.

In the recording, provided to ABC News by the Sanders campaign, a woman's voice asks a man on the other end for, among other things, his impression of both talking points that are favorable to Clinton as well as a series of attack lines against the Vermont senator.