Fusion has refused to tell congressional committees who paid for the dossier or reveal its sources.
Trump is referring to news of two executives from Fusion GPS who chose to remain silent yesterday during a private meeting with the House Intelligence Committee.
Two executives of a firm that helped produce an opposition-research dossier that makes salacious claims about President Donald Trump's ties to Russian Federation refused to answer questions Wednesday in a private meeting with the House Intelligence Committee. Steele had been retained by Fusion GPS and was one of the main authors of the original dossier. His attorney released a statement following the interview saying that he did not reveal the names of Fusion's clients.
Steele's work yielded the so-called "dossier", which is a series of memos that outline raw intelligence, much of it unverified, that alleges collusion between Russian agents and the Trump campaign. The dossier, compiled by political research firm Fusion GPS, has been under federal investigation since it leaked in January - but neither its funder nor its claims have been publicly verified.
In early 2016, Fusion GPS began investigating Trump at the request of an unnamed Republican client.More news: Demi Lovato shares powerful 'then' and 'now' photos documenting eating disorder
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Not only would it violate "the First Amendment rights" of Fusion GPS' higher-ups to be forced to testify, Levy went on to write, but it would also damage their ability to conduct "confidential opposition research in an election".
"No American should experience the indignity that occurred today", Levy said Wednesday.
Another co-founder, Glenn Simpson, is under subpoena for a later date. "We've done that with other committees, and will continue to do so".
Catherine Herridge is an award-winning Chief Intelligence correspondent for FOX News Channel (FNC) based in Washington, D.C. She covers intelligence, the Justice Department and the Department of Homeland Security.