Two Republican senators pushing for a criminal investigation into former British spy Christopher Steele say his infamous dossier on President Trump’s ties to Russia provided the “bulk of allegations” used by the Justice Department to obtain a wiretap on a former Trump campaign adviser. Sens. Chuck Grassley and Lindsey Graham made the allegation in a letter sent to the FBI and Justice Department last month but released Monday. In a less-redacted version of the letter released Tuesday, the senators say Steele may have “materially misled the FBI” about his contact with reporters on allegations in the dossier, The Wall Street Journal reports. Steele, whose research for the dossier was partly funded by the Democratic National Committee, has found himself at the center of a political firestorm after a Republican memo released last week alleged the FBI relied on his report to obtain a surveillance warrant for former Trump campaign adviser Carter Page. Graham and Grassley, the chairman of the Senate Judiciary Committee, say the Justice Department relied “heavily” on Steele’s findings in its warrant application, a claim denied by Democrats.