PHOENIX (AP) Horne and aide Kathleen Winn are fighting civil allegations that they worked together to sidestep election laws during his 2010 run for office.
An FBI agent this week testified that a chain of emails and cellphone records show Horne talked to Winn while she worked with a campaign consultant about an ad.
Both deny illegally coordinating spending while she ran a committee called Business Leaders for Arizona.
Horne could take the stand Wednesday.
Yavapai County Attorney Sheila Polk ordered Horne to return nearly $400,000 to donors and also is seeking three times that amount in fines.