Internal investigators for the departments of Justice, Defense, the Interior and Homeland Security will investigate how security officials prepared for and responded to last week’s pro-Trump rally in Washington that descended into a riot at the U.S. Capitol, officials announced Friday.

The inspectors general for all of those agencies will review what people knew and how they prepared for that day, Jan. 6, along with their actions during the riot that resulted in five deaths, according to news releases. Questions have swirled about how such an important government building — with so many security agencies available to assist — could be overcome by a mob of people wielding bats, bear spray and brute force.

Some current and former law enforcement officials have called the disturbing incident an intelligence failure, in that federal agencies did not seem to have a sense of the urgency or danger leading up to the attack. Others have argued it was less a failure of intelligence than a failure to act on the intelligence gathered, much of it from public discussions online.

The Washington Post reported earlier this week that the FBI’s Norfolk office circulated an intelligence report a day before the riot warning of talk online to storm Congress, break windows, push in doors and “get violent. . . . Get ready for war.” FBI officials said they shared that information the same day with other law enforcement agencies, but some senior officials outside the FBI have said they never saw it.

FBI Director Christopher A. Wray and acting attorney general Jeffrey Rosen were not briefed on the document because it was considered a raw intelligence product and investigators had not identified those responsible for the posts, according to officials familiar with the matter who, like others, spoke on the condition of anonymity due to its sensitivity. Wray was briefed in advance about violent chatter online more broadly and about information the FBI’s sources were relaying concerning suspected extremists intending to travel to the Capitol.

Dozens of people in D.C. on the day of the riot were previously identified on a government watch list as potential terrorist suspects, according to people familiar with the matter.

The multiagency review was announced as the nation’s capital is on edge, with a growing security presence aimed to dissuade any further violence this weekend or at President-elect Joe Biden’s inauguration on Wednesday. Government officials are sealing off streets and some large public areas in hopes of preventing a repeat of last week’s chaos.

The Justice Department review “will include examining information relevant to the January 6 events that was available to DoJ and its components in advance of January 6; the extent to which such information was shared by DoJ and its components with the U.S. Capitol Police and other federal, state, and local agencies; and the role of DoJ personnel in responding to the events at the U.S. Capitol on January 6,” Inspector General Michael Horowitz’s office said in a statement.

Horowitz’s office will examine “whether there are any weaknesses in DoJ protocols, policies, or procedures that adversely affected the ability of DOJ or its components to prepare effectively for and respond to the events at the U.S. Capitol,” the statement said, adding that his office may also examine other issues that arise during the course of his investigation.

The review is unlikely to produce quick results, since inspector general investigations typically take months or years to complete, and this one spans four large government departments.

The announcement of such a probe, as the FBI’s sprawling national investigation into the attack is barely a week old, underscores the degree of concern in government circles that vital intelligence may have been missed or mishandled. In his statement, Horowitz said his office “is mindful of the sensitive nature of the ongoing criminal investigations and prosecutions” and will “take care to ensure that the review does not interfere with these.”

Law enforcement officials insisted Friday that effort was only gaining steam, saying they have filed 98 criminal cases against people and opened nearly 300 cases on individuals under investigation for rioting. Those figures, they said, would continue to grow as they examine more than 100,000 tips received from the public.

“To those of you who took part in the violence, here’s something you should know: Every FBI field office in the country is looking for you,” said Steven M. D’Antuono, head of the FBI’s Washington Field Office. “As a matter of fact, even your friends and family are tipping us off.”

In a letter to Pentagon leaders, a senior official from the Defense Department inspector general’s office said its review will begin this month and examine “requests for DOD support leading up to the planned protest and its aftermath at the U.S. Capitol complex, the DOD’s response, and whether the DOD’s actions were lawful and supported by requirements according to regulations and applicable guidance.”

Officials with D.C. police and the Capitol Police have accused the Defense Department of responding slowly as rioters forced their way into the Capitol building, saying that senior officials initially denied their request for urgent help and took hours to get members of the D.C. National Guard on site to assist.

Pentagon officials, in turn, have said local officials and authorities at the Capitol sought only limited help ahead of time from the D.C. National Guard — which because D.C. is not a state is commanded by the Defense Department — and had unrealistic expectations about how quickly a force of part-time soldiers can deploy.

Acting defense secretary Christopher C. Miller, responding to the review Friday, promised the Pentagon’s cooperation and said Americans deserve transparency about what occurred. “We are proud of the efforts of DOD personnel to secure the Capitol on January 6th when called upon on and throughout the Presidential Inaugural events next week,” he said.

In the months before the riot, military leaders, scarred by criticism over their role in President Trump’s heavy-handed response to racial justice protests in June, have sought to distance themselves from the polarized politics surrounding November’s election and Trump’s attempts to overturn its result.

But in the wake of last week’s events, the Pentagon has mobilized a much larger force of National Guard from D.C. and states across the country to be in place ahead of Biden’s inauguration. There are about 10,000 guardsmen on duty in Washington, a force that could grow to as much as 25,000 by next week. And unlike the small force of about 340 guardsmen activated before the Capitol riot, some now positioned in D.C. are armed.

Separately, the Capitol Police inspector general has told lawmakers that its office also will review events surrounding last week’s melee and suspend all other casework while it does so, according to a congressional aide.

“It’s absolutely vital,” said Sen. Chris Murphy (D-Conn.), “that we have a clear understanding of the U.S. Capitol security breach.”

House Speaker Nancy Pelosi (D-Calif.) also announced Friday that she has asked retired Lt. Gen. Russel Honoré to conduct a separate review, which would subject “the whole complex” to scrutiny. Honoré is best known for taking command of the task force overseeing the U.S. military response to Hurricane Katrina in 2005, after other government agencies foundered and appeared unable to help many of those who needed food and shelter after the storm.

Some lawmakers have asked the Government Accountability Office to examine those same issues, but that agency has not yet announced its decision on the request.

Aaron C. Davis, John Wagner and Matt Zapotosky contributed to this report.