Former Massachusetts Treasurer Tim Cahill is expected to take the witness stand for a second day as prosecutors question him about taxpayer-funded lottery ads they say he ran to promote his faltering 2010 gubernatorial campaign.

Cahill spent more than two hours on the witness stand Thursday, answering questions from his lawyer. He is expected to be cross-examined by prosecutors today.

In his testimony, Cahill insisted that he approved the ads to defend the lottery after the Republican Governors Association ran a series of ads attacking Cahill and his management of the lottery, pension fund and treasury.

Cahill said lottery executives were concerned that the attack ads could damage the lottery's image and hurt sales.

Prosecutors, however, have said Cahill schemed to "reach into the pocket" of the lottery to help his struggling campaign.