…Several months later, when it became clear that Donald Trump was the likely GOP candidate who would win the primary (March/April 2016), Hillary Clinton signed-on to purchase the opposition research from Glenn Simpson and Fusion GPS. (Source)
The graphic below is very informative. Start at the top at “Searches” (Nellie Ohr’s illegitimate searches of the NSA/FBI database) and follow the arrows clockwise back to the top where the FISA court approves the spy warrant on Carter Page and by extension the entire Trump campaign team. ABN