>Why were they after Trump before he even announced he was running for office?
Because he was questioning Obama's birth origin?
"February 10, 2011: Trump's speech to CPAC in which he said he was thinking about running for president: 'Our current president came out of nowhere. Came out of nowhere. In fact, I'll go a step further: The people that went to school with him, they never saw him, they don't know who he is. It's crazy."
https://www.vox.com/2016/9/16/12938066/donald-trump-obama-birth-certificate-birther