Dozens of protesters have been charged with offences after storming the Capitol building, with one allegedly found with a semi-automatic rifle and 11 Molotov cocktails.
At least 55 people are being charged with crimes related to the siege by supporters of President Donald Trump in the wake of his election defeat.
Michael Sherwin, the US attorney in Washington said that prosecutors and the police department are working to identify suspects, but the Capitol police’s failure to arrest people as they left the building has made the task of charging people harder.
He revealed that the police, FBI agents and other law enforcement had to rely on social media posts to identify suspects.
“Look, we have to now go through cell site orders, collect video footage to try to identify people and then charge them, and then try to execute their arrest,” he said.
“So that has made things challenging, but I can’t answer why those people weren’t zip-tied as they were leaving the building by the Capitol Police.”
Capitol Police only arrested 14 people at the riot, allowing hundreds more to leave without arrest.
Steven Sund, the Capitol’s police chief, resigned on Thursday over his force’s failure to protect the building.
Prosecutors have so far filed 40 cases on charges including unlawful entry, assault and firearms offences against the protesters, as well as a further 15 complaints in the pipeline for criminal cases linked to the breach of the Capitol, including illegal possession of a firearm and theft.
Police have announced that they so far arrested nearly 70 people, on various charges.
Some more serious offences such as the opening of files which could constitute a breach of national security were also being looked at by the Justice Department, with Mr Sherwin admitting that the department was still working to understand the scope of the problem.
One man arrested near the Capitol allegedly has in his possession a semiautomatic rifle and 11 Molotov cocktails.
Another of the protesters, Mark J Leffingwell, was accused of assaulting a Capitol police officer in a hallway in the Senate wing of the building.
The complaint by officer Daniel Amendola said that Mr Leffingwell “attempted to push past me and other officers.”
“When he was deterred from advancing further into the building, Leffingwell punched me repeatedly with a closed fist. I was struck in the helmet that I was wearing and in the chest.”
According to the complaint Mr Leffingwell later “spontaneously apologised” for hitting the officer.
Prosecutors are also looking at charges against Christopher Alberts from Maryland, who was accused of illegally carrying a Taurus 9-millimeter pistol at the riot.
According to the complaint, officers saw Mr Alberts leaving the Capitol with a bulge on his right hip.
When they stopped him, they allegedly found the pistol had one round in the chamber, as well as a magazine filled with 12 bullets.
Officers went on the find that he was wearing a bulletproof vest and had a gas mask in his backpack.
Once he was arrested, the complaint read that Mr Alberts told the police that they were for “personal protection” and did not intend to harm anyone.
One police officer, Brian Sicknick, was injured while on duty during the protest on Wednesday before dying late on Thursday after being taken to hospital.
Capitol protesters charged following riot in Washington The British Journal Editors and Wire Services/ The Telegraph.