FBI looking for the would-be bomber in D.C.

https://www.fbi.gov/contact-us/field-offices/washingtondc/news/press-releases/fbi-washington-field-office-releases-video-and-additional-information-regarding-pipe-bomb-investigation
After looking at the video, my take-away is that it is of a female. A friend suggests Ashli Babbitt, which would explain both the military stride and the inability to find a living person.
Presumably, the backpack has DNA.