Meet the reporters behind the Trump dossier

Glenn Simpson, founder of Fusion GPS. Screenshot: Double Exposure Investigative Film Festival and Symposium in 2016

In fall 2015, Fusion GPS, an investigative firm run by former senior reporters at the Wall Street Journal, began working on a new assignment — a deep dive into Republican presidential candidate Donald Trump. The Washington Free Beacon, funded by a Republican backer of Trump rival Sen. Marco Rubio, was the client. Quickly, Fusion's researchers understood one big thing about Trump's business empire: It seemed inordinately weighted to Russia, and so they turned much effort to untangling that part of his business story.

Why it matters: Trump and the Republican-controlled Congress have sought to discredit Fusion as a tool of the Democratic Party. But the history of the firm's principals suggests no motive apart from the thrill of the chase, and of course earning serious money. The focus on Russia appears to have been a natural course of what they found.