CHICAGO -- A member of the Ricketts family is giving millions to a super PAC targeting Donald Trump.
USA Today reports Marlene Ricketts, the wife of T.D. Ameritrade founder Joe Ricketts, gave $3 million to Our Principles PAC.
It's been airing ads against Trump and sending out mailers ahead of states' primaries.
Trump responded a tweet that reads: "I hear the Rickets family, who own the Chicago Cubs, are secretly spending money against me. They better be careful, they have a lot to hide!"
The Ricketts family is not commenting.