Investigators now believe the attack on the US Capitol last week was not just a protest that spiraled out of control.
CNN reports that the belief, early in the probe, will demand significant investigation.
Evidence uncovered so far, including weapons and tactics seen on surveillance video, suggests the attack was planned.
The FBI says some participants at the Trump rally at the Ellipse, outside the White House, left the event early, perhaps to retrieve weapons.
They're also looking at travel and communications records to determine if they can build a case that is similar to a counterterrorism investigation.
Corruption prosecutors and agents are also engaging in the hunt for wrongdoers, thanks to their expertise in financial investigations.
The FBI reported that it has received more than 126,000 digital tips from the public regarding the attack on the Capitol.