Grassley wants details on Pentagon chief's personal email
"The use of private email in this context exposes information to possible hacks and intrusions by foreign intelligence agencies," Grassley, chairman of the Senate Judiciary Committee, wrote to Carter in a letter released on Tuesday. "As the Secretary of Defense, you are inevitably a prime target for foreign hackers. As such, the threat is real and compliance with the law is essential."
The letter comes after The New York Times reported late last year that Carter used a personal email during his first months in the Pentagon's top spot, including after it was revealed that Hillary Clinton had exclusively used a private email server during her time as Secretary of State. 
Citing the fallout over the Clinton revelations, Grassley added that it is "troubling" that Carter would use the personal email, "especially since you continued using that arrangement even after the risks of private use were made clear when news of Secretary Clinton’s use broke."
The Iowa Republican wants to know if Carter has provided all emails sent from his personal account to the Defense Department as part of the federal records requirement and why he used the personal email to begin with. 
He also wants details on if a review has been done to determine if Carter ever sent or received classified information through his personal email, and if any, separate, investigation has been done to determine if Carter's email was hacked. 
Grassley is also at the center of the Senate's investigation into Clinton's use of a private email server during her time at the State Department. The issue has dogged Clinton's presidential campaign, with Democrats arguing the probe is politically motivated. 
While the Republican response to Carter's email use has been muted compared to the fury over Clinton, Sen. John McCain (R-Ariz.) said late last year that the Senate Armed Services Committee, which he chairs, would be looking into it
Carter called his use of a personal email account a "mistake" but that he didn't use the account to send classified material. The Pentagon also released 34 pages of the Defense secretary's emails late last year. 
Grassley added in his letter to Carter that "other than acknowledging this practice as a mistake, what steps have you taken to see it is not repeated or followed by anyone else in your department?"