Co-founder of firm behind dossier tying Trump to Russia testifying next week

The co-founder of the firm who ordered a salacious dossier on President Trump will testify before the Senate Judiciary Committee next week.

Glenn Simpson’s opposition research firm, Fusion GPS, hired former British spy Christopher Steele to investigate then-candidate Trump.

The dossier produced by Steele claims Trump and the Kremlin had worked together to undermine Democratic presidential nominee Hillary ClintonHillary Rodham ClintonMueller asks WH staff to preserve all documents about Trump Jr. meeting: report OPINION | Hey Dems, Russia won't define 2018, so why not fix your party's problems instead? Russian lawyer who met Trump Jr. represented spy agency: report MORE’s campaign.

The unsubstantiated findings in the dossier were released to media outlets and published by BuzzFeed in January.

Simpson will testify before the committee on Wednesday. 

Senate Judiciary Chairman Chuck GrassleyChuck GrassleyFeinstein: Trump Jr. will be subpoenaed if he refuses to testify The next battle in the fight against human trafficking The Hill's 12:30 Report MORE (R-Iowa) demanded details on the dossier in a letter last May, and threatened to subpoena Fusion GPS in June.