Pictured: Some poor saps with backpacks. Unheard of in a college-dense city like Boston.
Reddit, 4chan, and some other Internet communities decided to comb through public footage of the Boston marathon. Their aim was to find the marathon bombers themselves, and to piece together the narrative behind the event. After all, they had all the same resources as the FBI, minus the criminal database, the forensic evidence, witness testimony, and all of those other "extra" things.
These internet detectives assembled an extensive gallery of "suspicious" people. Tabloids found these pictures, printed them, and circulated them. When the FBI released blurry photos of the two suspects, the Internet communities doubled down on their efforts. They reduced their list of suspicious people to a middle-eastern-looking guy named Sunil Tripathi, who had gone missing prior to the bombing. People ate up the possibility that the person responsible for the bombings had been identified.
And then it turned out that the Internet got it completely wrong. It wasn't Sunil Tripathi. It was two Chechen brothers (which must have been a relief for middle-eastern people dealing with unwarranted backlash about this already). Of course, that didn't stop people from going on a completely misinformed witch hunt for the first guy before the debunking. And it isn't stopping crackpots from trying to continue that witch hunt. Oops.
This is internet vigilantism - and in this case, it misfired. These events demonstrate the power of the online sphere in shaping public opinion. The Internet can also have a stake in the action themselves, with users often getting involved in pursuing criminals and other targets. This phenomenon has happened before, and it will probably happen again. What is the anatomy of online vigilante justice, and what can be learned from its failure here?