In a significant development, authorities have arrested a suspect for the first time in connection with a case that has puzzled investigators for years. The incident, entwined with the dark events of the Capitol siege, has inspired numerous conspiracy theories and remained an elusive mystery in American history.

An official, speaking anonymously due to lack of authorization to publicly discuss this ongoing investigation, disclosed that the arrest occurred on Thursday morning. The suspect is a male, although further details, including potential charges, have not been released.

The pipe bombs, discovered on January 5, 2021, were strategically placed near the Democratic and Republican National Committee offices in Washington, D.C. Although the bombs were safely defused without causing harm, the FBI noted their potential to be deadly.

Since the incident, authorities have sought public assistance in identifying a mysterious figure captured on surveillance footage. Investigators have grappled with basic questions about the suspect’s identity, motives, and any possible link to the Capitol riot that erupted a day later when supporters of then-President Donald Trump stormed the building to contest his electoral defeat to Joe Biden.

In pursuit of new leads, the FBI released additional information last January, including an estimated height of 5-foot-7 for the suspect, along with previously unseen footage depicting the individual placing one of the explosive devices.

The bureau had for years struggled to pinpoint a suspect despite hundreds of tips, a review of tens of thousands of video files and a significant number of interviews.

In the absence of harder evidence, Republican lawmakers and right-wing media outlets promoted conspiracy theories about the pipe bombs. House Republicans also criticized security lapses, questioning how law enforcement failed to detect the bombs for 17 hours. Dan Bongino, the current FBI deputy director, floated the possibility last year before being tapped for his job that the act was an “inside job” and involved a “massive cover-up.”

The FBI’s top two leaders, Bongino and Director Kash Patel, sought to breathe new life into the investigation despite having openly disparaged the bureau’s broader approach to the Jan. 6 siege and despite Trump’s pardons on his first day back in office of the rioters who stormed the Capitol, including those who violently attacked police with poles and other makeshift weapons.

In a long post on X last month, Bongino wrote that the FBI had brought in new personnel to examine the case and “dramatically increased investigative resources” along with the public award for information “to utilize crowd-sourcing leads.”