ABC
A question of verbiage: when do you go from "whistler blower" or "a guy with information?" If you are not surfacing information that wouldn't otherwise be available there isn't a whistle to blow, no?
This is a major issue for Trump if the new witness has information that conflicts with Trump. Otherwise, this might be a sign from the impeachment side that there wasn't enough gas in the tank with the first whistle blower.