"I'm not going to comment on what he may or may not have done for the United States government, but in the emails that were on Hillary Clinton's private server, there were conversations among her senior advisors about this gentleman," he said on "Face the Nation." Cotton was speaking about Shahram Amiri, who gave information to the U.S. about Iran's nuclear program.
So we're not 100% sure that the Iranians found out that one of their scientists was providing information to the US from Hillary's e-mails. We'll never be. However, we are sure that they found out about him helping the US and then killed him for doing so. I'm assuming he didn't just randomly confess, though.
I know she didn't intend for him to be outed to the Iranians, but when you're extremely careless about intelligence matters, sometimes your enemies capitalize on them. And people die.
We'll obviously never know what happened, because the Iranians aren't going to tell us how they found out this scientist was helping us. It's just something to think about when one of Hillary's supporters tells you the e-mail thing "doesn't matter".