Six months have passed since rioters stormed the US Capitol building in the violent 6 January insurrection that left five people dead.
Yet, authorities have failed to track down one key suspect who placed pipe bombs around Washington DC, on the eve of the attack.
Images of the suspect captured through surveillance camera showed an unidentified person wearing a backpack and grey hooded sweater placing two pipe bombs around the Capitol Hill area on 5 January, just hours before hordes of rioters, including many Trump supporters, would storm the US Capitol Building.
One bomb was placed near the headquarters of the Democratic National Committee, while another was placed behind the Republican National Committee’s HQ. The devices contained explosive powder and were fitted with egg timers.
They were quickly discovered at around 1pm, however, on 6 January, shortly after rioters began to face off with Capitol Police officers.
While at least 500 people have since been arrested in connection with the Capitol riot, many, including the pipe bomb suspect, have so far managed to elude authorities.
According to the Associated Press, the FBI is still looking around 300 more suspects who have been labeled “unidentified” in pictures from the insurrection.
The first wave of arrests, the press agency said, were focused largely on the “easy targets” in the investigation.
Now, however, the FBI faces the task of continuing to identify scores of other suspects who have been more difficult to track down.
During a House Oversight Committee hearing back in May, DC Metropolitan Police Chief Robert Contee acknowledged that a suspect still had yet to be identified in the pipe bomb incident.
“That investigation continues on,” he said, according to The Huffington Post.
Officials have also suggested that the pipe bomb planting could have been a “diversion” to distract police.
In his own testimony, Capitol Police Inspector General Michael Bolton said that when the pipe bombs were discovered on the morning of 6 January, three teams were dispatched to investigate, leaving just one team to protect the Capitol.
“If those pipe bombs were intended to be a diversion, it worked,” Mr Bolton said.
The FBI is still offering a $100,000 reward for information that leads to the identification of the suspect.
Anyone with information is asked to contact the FBI at 1-800-CALL-FBI or send in tips online anonymously at tips.fbi.gov.