Indeed, there were several indicators of the potential for violence on Jan. 6. Federal law enforcement officials knew that members of militias such as the Oath Keepers and far-right groups such as the Proud Boys planned to travel to Washington, some potentially with weapons. Many adherents of QAnon, a dangerous conspiracy theory that has emerged as a possible domestic terrorism threat, were also expected to attend a protest rally where Mr. Trump spoke before the attack.
In addition, the F.B.I.’s office in Norfolk, Va., produced a report a day earlier warning of possible violence and mentioned people sharing a map of tunnels at the Capitol complex. However, the information was unverified, and a portion quoting a warning of an impending “war” appeared to come from a single online thread.
The F.B.I. provided the report to the Capitol Police, although its former chief, Steven A. Sund, has said it never made it up the ranks.
Mr. Wray said that F.B.I. officials relayed the Norfolk information on at least three occasions to other law enforcement agencies. He said that he had not seen the report until after the riot, but that the handling of it was typical for such intelligence.
Senator Lindsey Graham, Republican of South Carolina, asked what Capitol Police leaders should have done had they seen the Jan. 5 report.
“I really want to be careful about not to be an armchair quarterback,” Mr. Wray said. He later said he did not have a “good answer” as to why Mr. Sund did not get the report.
With the signs pointing to violence or worse on Jan. 6, Senator Richard Blumenthal, Democrat of Connecticut, pressed Mr. Wray on why the F.B.I. did not “sound the alarm in some more visible and ringing way.”