Authorities have charged hundreds of people for allegedly participating in the January 6th right of the U. S Capitol. But one person still eludes them. The person who placed two explosive devices in Washington D. C the night before Here are Tim Mack and Dina Temple Raston from NPR's investigations unit. The crime the FBI is trying to solve happened between 7:38:30 P.m.. That's when authorities believe the suspect planted two pipe bombs just blocks from the Capitol. The suspect was wearing a gray hooded sweatshirt. Ah Cove in mask and expensive sneakers. They were Nike Air Max speed turf with the yellow logo. Surveillance cameras captured the figure walking through a Capitol Hill neighborhood the night before the January six riots. One of the bombs was placed on a park bench near the headquarters of the Democratic National Committee, the other behind Republican Party headquarters and surveillance footage caught the suspect walking look at how close their feet are to each other. So that is a narrow base of gate. That's Dr Mike Nierenberg, who wrote the textbook on Forensic Gait analysis. He helps identify people based on how they walk. He's watching along with us as we review surveillance video from that night immediately. What you notice is the arm swing of the person on that left arm. There's not a lot of rotation in their upper half of their body, their torso. The FBI has asked for help finding someone who walks like this. The explosive devices they found were made from one by eight inch galvanized steel pipes. Plumbers typically used And they had plastic kitchen timers mounted on top. The con Jews been around set. The FBI said the explosive inside was homemade black powder, which could be a mix of just about anything that will ignite. Typically, it includes salt Peter and sulfur and gunpowder. The FBI is yet to say exactly what explosive was