WASHINGTON/NEW YORK (Reuters) - The U.S. Justice Department moved swiftly to bring federal charges against 53 individuals accused of violence during nationwide protests that swept across the United States calling for an end to police brutality.

Attorney General William Barr promised a crackdown on members of the anti-fascist movement known as antifa and other extremists he blamed for helping to drive the violence.

But a Reuters examination of federal court records related to the charges, social media posts by some of the suspects and interviews with defense lawyers and prosecutors found mostly disorganized acts of violence by people who have few obvious connections to antifa or other left-wing groups.

Reuters reviewed only federal cases, both because of the allegations by the Justice Department about the involvement of antifa and similar groups, and since federal charges generally carry harsher penalties. In some of the charging documents reviewed by Reuters, no violent acts are alleged at all.

The Department of Justice declined to comment on Reuters findings and referred to an interview that Barr gave to Fox News on Monday. He said there that while his department had some investigations under way into antifa, it was still in the initial phase of identifying people.

Looting and violence broke out at some of the hundreds of largely peaceful demonstrations over the past week sparked by the May 25 death of George Floyd, an African American, after a white Minneapolis police officer pinned him with a knee to the neck for almost nine minutes.

The policeman, Derek Chauvin, has been charged with second-degree murder, and three other officers with aiding and abetting.

While Barr and President Donald Trump have repeatedly singled out antifa, an amorphous movement of primarily leftist anti-authoritarians (the name is derived from anti-fascist), as a major instigator of the unrest, the term does not appear in any of the federal charging documents reviewed by Reuters. It is possible that more evidence could emerge as the cases progress.

Only one group was called out by name in a federal complaint: the so-called boogaloo movement, whose followers, according to prosecutors, believe in an impending civil war.

Hate group experts say boogaloos followers are largely an assortment of right-wing extremists. Prosecutors alleged three men affiliated with the movement plotted to set off explosives in Las Vegas in the hopes of touching off rioting before a protest.

The three suspects are scheduled to appear in federal court on Monday and have not yet entered a plea. Their lawyers did not respond to requests for comment.