The "man on the roof" was one of the first suspects of debate for the amateur sleuths who are now trying as feverishly as the professionals to solve the Boston Marathon bombings.
In a picture taken by a Reuters photographer and circulated widely online, he is a stooped, silhouetted figure caught midstep on a building above the finish line, just as the explosion blasts on the ground below. Who's that guy? Twitter asked. And the debate kicked off. So far no one appears to know, and other than being a literally shady figure, there's nothing in the picture to link him to the crime occurring below. The online sleuths move on, for now, continuing their inspection of thousands upon thousands of video and photographs – searching for the next out-of-place face that may be responsible.
On this occasion, we can be grateful for our shutterbug obsession, even as the Internet revealed how quickly unsubstantiated rumours can spread. (As of late Wednesday afternoon, there were reports that a suspect had been identified on a security camera, with official confirmation said to be forthcoming.) And surely there are other clues hidden somewhere in the mass of digital evidence captured by the race-cheering crowd in Boston: Someone, we hope, just had to be snapping a picture or filming some careless video when those two pressure cooker bombs, carried in black bags, were left on the sidewalk. The authorities have been scouring them, and Wednesday, as runners flew home, airport security reminded them to make sure they had given police any pictures or video from Monday's tragic race.
On Reddit, users have taken the requests for help to heart and started pouring through the visual record themselves, tossing around their own random theories. "Has anyone looked at people with strollers?" one poster asked at findbostonbombers. Someone pointed out a "Unabomber look-a-like" caught on video. A guy with a backpack wearing "a Navy Seal Team hat" was flagged. By midday, several threads were narrowing in on a description of a person of interest: a white man in a gray hoodie and black jacket, wearing a baseball cap backward. But earlier, attention had fallen on the "blue robed guy," holding a "heavy" backpack, even analyzing the angle of the shoulder straps. "The guy is trying to look nonchalant, maybe?" the poster said.
The efforts may be well-meaning – in the face of senseless tragedy the need to do something is overwhelming and given the sheer pile of evidence, you might argue, why not have extra eyes? It's possible an armchair detective will catch an important incongruity in a picture – and if so, let's hopes he or she avoids boasting or speculating online and tries to contact the FBI.
But there's an uneasy whiff of vigilantism to the comments, heightened by the natural response to a crime that makes people justifiably angry. Labelling someone a suspect in a terrorist plot isn't the same as tagging a buddy's stupid party pranks, and yet much of the discussion felt just as causal.
The Internet has proven its ability recently to aid both investigators and victims of crime. In the rape case in Steubenville, Ohio, confessional tweets became evidence. And the father of Rehtaeh Parsons, who died by suicide this month, credited the Anonymous website with spurring Halifax RCMP to reopen the investigation into the alleged sexual assault suffered by his daughter; Anonymous announced it had the names of the boys it said had been involved and threatened to release them if the police didn't act.
But as comments pile up online, they take on a discomfiting energy, the kind that turns casual speculation into fact. As an Atlantic article observed, we need to be wary of the tone that travels through these Boston Marathon threads. "It doesn't matter that it's happening in a forum," writer Alexis Madrigal argued, "and not around a burning cross."
Even if the example is severe, the caution is valid. In fairness, Reddit users are already having that discussion.
One popular post reminded people to be careful where they point fingers with this question: "Does anyone remember Richard Jewell?" the thread asks.
In 1996, Jewell was a security guard at the Atlanta Olympic Games, who found a bomb in a backpack and manage to evacuate the area before it exploded, saving many lives. But he was suspected of planting the bomb himself, and before he was cleared (and the real bomber arrested), he had been subjected to public shame and judgment. The poster cautions: "You should be very very careful about picking and choosing who you think might have killed three people and wounded many more, based on where they were standing and if they were carrying a backpack or not."
A misplaced suspicion, misused by a tense crowd desperately seeking justice, would only add to the grief we all feel. And it won't get us closer to answers.