Perhaps the most reasonable of all the theoretical misinformation involves the suspicious "man on the roof" photo. Taken by college student Dan Lampariello, the photo shows a figure walking on the rooftop of a building near the finish line, just as the bomb exploded. However, a correspondent with the International Data Group (IDG)news service told Snopes.com that the man photographed was walking on a balcony that adjoins IDG offices, an area where workers commonly take breaks. When asked about the image, authorities said they're processing a lot of photographic evidence, but could not comment on specific leads at the moment.
Although authorities say they're "very close" to identifying a suspect, there appears to be no shortage of conspiracy theories, misinformation and jokes.
"You see this after every tragedy," Radford said. "After 9-11, there were jokes. After the Space Shuttle Challenger, within days, there were jokes...That's just how people are."