First of all, no they don't look like everyone else. Their backpacks look large and heavy, and unlike the other people in the photo, they are wearing heavy jackets. Second, if these two are not the real perpetrators, they would quickly come forward and be happy to speak with the FBI to clear things up. Time will tell. I doubt this will happen!
Saudis warns U.S. that 9/11 responsibility law would erode investor confidence in America (Reuters)
from the article: FBI releases images of Boston Marathon bombing suspects