"We got hacked, most likely from the Bass campaign," Caruso said at an afternoon news conference, referring to his opponent in the Los Angeles mayoral race, Karen Bass. "It's a fake e-mail and we're tracking it down."
But there's no proof at this point that the email came from the Bass campaign.
Sarah Leonard Sheahan, a spokesperson for Bass, said: "This is just another lie from Rick Caruso, who has lied about not being a Republican, has lied about being anti-choice and has lied about his failed leadership at USC."
Also on Thursday, Bass denied allegations that a $100,000 full-tuition scholarship she received from USC's social work program has any relation to a federal corruption case involving City Councilman Mark Ridley-Thomas.
Bass insisted that she obtained the USC degree to become a "better advocate for children and families," and she balked at comparisons to Ridley-Thomas, who is facing federal corruption charges involving, in part, a full scholarship his son received to the USC social work program.
"This case has nothing to do with me, other than in a middle of a political campaign, Rick Caruso is trying to take advantage," Bass told reporters.
City News Service contributed to this report.