Does the FBI normally tell people they are investigating that they are investigating them?
And the FBI did warn him and his campaign that Russia would try to infiltrate the campaign.
His response was to go on TV and ask them to release Clinton's e-mails
Yes, Horowitz stated it 30 minutes ago. If you aren't watching the hearing then stop posting here. He literally stated its normal protocol in counter surveillance. They weren't investigating Trump himself, they were investigating people who volunteered and wasn't being paid, working on his campaign. It's normal protocol to brief him on whats going on.