The FBI on Thursday made an arrest in the nearly five-year investigation into who placed pipe bombs in Washington on the eve of a riot at the US Capitol on January 6, 2021.
Brian Cole of Woodbridge, Virginia, has been charged with use of an explosive device, the Department of Justice said, and there could be more charges to come.
The arrest is the first time investigators have settled on a suspect in an act that had long puzzled law enforcement, spawned a multitude of conspiracy theories and remained an enduring mystery in the shadow of the violent Capitol siege, a dark chapter of American history.
"Today's arrest happened because the Trump administration has made this case a priority," Attorney General Pam Bondi told reporters. "The total lack of movement on this case in our nation's capital undermined the public trust of our enforcement agencies."
The pipe bombs were placed on the evening of January 5, 2021, near the offices of the Democratic and Republican national committees in the District of Columbia. Nobody was hurt before the bombs were made safe, but the FBI has said both devices could have been lethal.
In 2023, the FBI raised the reward for providing information that led to an arrest from $100,000 to $500,000. In January this year, the agency released more video footage of the suspect planting one of the bombs.
Ms Bondi said administration officials have "worked tirelessly for months sifting through evidence", saying that there was no new tip, just more attention focused on the case.
US Attorney for Washington Jeanine Pirro described efforts to find the perpetrator as "like finding a needle in a haystack".
"When you attack American citizens, when you attack our institutions of legislation, when you attack our nation's capital, you attack the very being of our way of life," FBI Director Kash Patel said.
January 6, a day after the bombs were placed, was the day Congress was set to ratify Joe Biden's victory in the 2020 elections.
That same day, a mob of President Donald Trump's supporters stormed the Capitol building in Washington over claims from him and his Republican allies that the election had been rigged.
