WASHINGTON (AP) — The FBI made an arrest on Thursday in its nearly 5-year-old investigation into who placed pipe bombs in Washington on the eve of the Jan. 6, 2021 riot at the U.S. Capitol, a law enforcement official told The Associated Press.

The arrest marks the first time investigators have settled on a suspect in a case that has perplexed law enforcement, spurred numerous conspiracy theories, and remained a significant mystery in the context of the violent Capitol siege.

The official who described the arrest was not authorized to publicly discuss the case, speaking on the condition of anonymity. The suspect is a man, and further details about the charges against him were not disclosed.

The bombs were left on the evening of Jan. 5, 2021, near the Democratic and Republican national committees' offices in D.C. Thankfully, there were no injuries reported as the devices were safely disarmed, but the FBI had stated that both devices could have been deadly.

Law enforcement agencies had struggled to identify a suspect despite reviewing countless surveillance videos and tip-offs from the public. The FBI was intent on finding the person seen on camera, focusing on who might have the motive and connection to the following day's riot where supporters of President Donald Trump attempted to disrupt the electoral certification.

In January, the FBI released additional footage of the incident and updated the public on their search efforts, stating the suspect was approximately 5'7 tall.

Over the years, the investigation has led to various conspiracy theories promoted by some lawmakers and media, questioning the lapses in security that allowed the bombs to remain undiscovered for 17 hours. Investigative efforts have intensified since the change in FBI leadership, indicating a renewed commitment to resolving this troubling case.

“We have significantly boosted investigative resources, increased public reward offers for information, and brought in new personnel to ensure this case remains a top priority,” an FBI representative communicated in a recent statement.