The authorities released surveillance video, offered a $US500,000 ($A755,646) reward and received hundreds of tips in a years-long search for the suspect they believe was involved in the incident that took place nearly five years ago.
The footage, from January 5, 2021, showed a person putting a bomb near a bench outside the Democratic National Committee building. The suspect placed another bomb at the Republican headquarters. Both sites are near the Capitol.
The suspect is Brian Cole, Jr, Bondi said. Cole, 30, of Woodbridge, Virginia, lives with his parents and works for a bail bond company, one of them said, according to a source briefed on the matter.
The bombs were discovered on the same day supporters of Trump stormed Congress in an attempt to stop Congress from certifying Democrat Joe Biden's 2020 presidential election victory.
Police deactivated the bombs and neither exploded.
In the January 6, 2021, melee at the Capitol, rioters surged past police barricades, assaulting about 140 officers and causing more than $US2.8 million ($A4.2 million) in damage.
Trump pardoned nearly everyone criminally charged for participating in the riot, some 1500 people, when he returned to office in January.
