Investigators are pursuing more than 150 suspects for prosecution, a total that is almost certain to grow, an official said. Analysts are also scouring intelligence to identify any role that domestic terrorist organizations or foreign adversaries may have played in radicalizing Americans who were among the rioters, according to a law enforcement official briefed on the investigations.

Some indication had emerged that at least some assailants initiated a more organized attack, Representative Tim Ryan, Democrat of Ohio and the chairman of the House subcommittee that has oversight of the Capitol Police, told reporters on Monday. Initial reports on Wednesday afternoon about pipe bombs planted at the nearby Republican and Democratic Party headquarters drew some law enforcement attention away from the breach that was unfolding at the Capitol, Mr. Ryan said, suggesting a “level of coordination.”…

The F.B.I. has moved quickly to ease some bureaucratic hurdles to making arrests, and it has received more than 70,000 photographic and video tips after asking for the public’s help in identifying suspects. Agents were also scrubbing airline passenger manifests and video of air travelers to and from Washington to find potential suspects.