White House ethics officials learned of Trump’s repeated use of personal email when reviewing emails gathered last fall by five Cabinet agencies to respond to a public records lawsuit. That review revealed that throughout much of 2017, she often discussed or relayed official White House business using a private email account with a domain that she shares with her husband, Jared Kushner.

The discovery alarmed some advisers to President Trump, who feared that his daughter’s practices bore similarities to the personal email use of Hillary Clinton, an issue he made a focus of his 2016 campaign. Trump attacked his Democratic challenger as untrustworthy and dubbed her “Crooked Hillary” for using a personal email account as secretary of state.

Some aides were startled by the volume of Ivanka Trump’s personal emails — and taken aback by her response when questioned about the practice. Trump said she was not familiar with some details of the rules, according to people with knowledge of her reaction.