Pro-Trump protester clash with Capitol police during a rally to contest the certification of the 2020 U.S. presidential election results by the U.S. Congress, at the U.S. Capitol Building in Washington, U.S, January 6, 2021.
Pro-Trump protester clash with Capitol police during a rally to contest the certification of the 2020 U.S. presidential election results by the U.S. Congress, at the U.S. Capitol Building in Washington, U.S, January 6, 2021. Reuters / Shannon Stapleton

The U.S. Department of Homeland Security's intelligence office was aware in advance about threats connected to the Jan. 6, 2021, attack on the Capitol, but failed to warn other law enforcement offices until it was too late, the department's internal watchdog has found.

The new report from the DHS inspector general paints a critical picture of the Office of Intelligence and Analysis (I&A), which it says failed at least three times to disseminate intelligence about the storming of the building by then- President Donald Trump's supporters, who wanted to block Congress' certification of his November 2020 election defeat.

More than 140 police officers were assaulted, as were members of the media. One of the rioters, Ashli Babbitt, died after she was shot by Capitol Police as she climbed through a doorway.

Since the attack, more than 775 people have been criminally charged.

"In the weeks before the events at the U.S. Capitol, I&A identified specific open source threat information related to January 6 but did not issue any intelligence products about these threats until January 8," the report says, adding that some of the missteps came from "inexperienced collectors" who received "inadequate training".

In one example, a field office division tried to share intelligence suggesting the right-wing group the Proud Boys planned to shut down the Washington, D.C. water system at 11:29 a.m. on Jan. 6.

The former chairman of the Proud Boys, Enrique Tarrio, was charged on Tuesday, just a few hours after the inspector general's report was released, for conspiring with fellow members to block President Joe Biden's election victory from being certified by lawmakers.

Other cryptic messages uncovered by intelligence-gatherers included people who openly discussed sharing maps of the U.S. Capitol building.

"I found a map of all the exits and entrances to the Capitol building," one person wrote to another on Jan. 2, 2021. "I feel like people are actually going to try and hurt politicians. Jan 6th is gonna be crazy."

In response to the report, John Cohen, a senior official with the Office of Intelligence and Analysis, said he concurred with the report's findings and recommendations, which call for additional training and more timely reporting on urgent open source threat intelligence.

"As Secretary (Alejandro) Mayorkas has said, the attack on the U.S. Capitol on January 6, 2021 was a violent assault on our democracy," a DHS spokesperson said.

The spokesperson added that the DHS "has strengthened intelligence analysis, information sharing, and operational preparedness" since the attack.