The Justice Department’s report on the FBI’s Crossfire Hurricane probe is the first official account of sources relied on by Christopher Steele to write a dossier that damaged President Trump, energized the FBI and ultimately proved to be untrue. The Justice Department inspector general’s report shows that an anonymous phone call with a Steele source provided the unverified conspiracy theory to trigger a Trump campaign wiretap. Mr. Steele talked to the FBI but refused to reveal his murky network. But the FBI was able to locate his “primary sub-source.” After interviewing the Moscow-based person three times in 2017, the results...