Don’t blame Rupert Murdoch. Blame the Internet.

Two men who appear to be innocent of any crime found themselves splashed on the cover of Thursday’s New York Post under the ominous headline, “BAG MEN.” The paper stated that the men, pictured sporting backpacks amid a crowd of spectators at Monday’s Boston Marathon, are being sought by federal officials for their alleged link to bombings that killed three people and injured almost 200 more.

The Post, now under fire for posting the images without any apparent confirmation that the men were being investigated, implied that it obtained the image from law-enforcement sources. But it’s the same one that was circulated widely the night before in online communities like Reddit and 4chan, both of which have rushed to conduct an investigation from Internet armchairs as federal law-enforcement officials coordinate a national manhunt. Now, the amateur e-sleuths’ most bandied-about “suspects” are finding themselves forced to proclaim their innocence. Message boards, meanwhile, are hosting an outbreak of squabbling over whether they’ve fingered the wrong guys, perhaps even creating the next Richard Jewell.

Much of the action is taking place on a newly created Reddit subsection called “findbostonbombers,” in which users proudly and furiously pore over photos and video footage of the attack, hunting for potential suspects, even as detractors urge caution.

The group spent much of Wednesday debating everything about the “bag men” photo and those two spectators. Why were they looking away from the race? Why did their bags seem to be sagging? Were they unusually heavy? They were two of the five suspects listed in this Google spreadsheet, described as “Backpack Bros.” Their race: “ethnic.” Their skin: “dark brown.”

Fear not, dozens of Reddit users insisted: we’re only sending these clues to the FBI. We’re publishing no names and linking to no Facebook pages. We’re just here to help.

And then it all got out of hand.

By Wednesday night, someone, somehow, had found both of the men’s Facebook pages, setting off a new round of allegations, self-congratulations, and calls for self-restraint from the Web detectives. As users from Reddit, 4chan, and an Internet forum called ar15.com swarmed the Facebook page belonging to a young high school student from Morocco with a bright blue tracksuit, he posted an update using Facebook’s mobile app: “Going to the court right now! Shit is real. But u will see guys I’m [sic] did not do anything.”

“There [sic] taking you to court?!” one of his friends asked. “You serious bro?!” asked another. “Shit dude...” posted a third. “No,” the young man replied, “I’m just going to tell them that it was not me.” “Careful dude,” a fourth friend wrote on the thread. “The whole Internet is watching you right about now.”

Within the hour, users had pored through his recent status updates and photos, finding evidence of a life in training—not for jihad, apparently, but for track and soccer, with a job at a Boston-area Subway restaurant. The Smoking Gun, which also had a look at the Facebook pages, found posts identifying the other man, also a Moroccan immigrant and Boston resident, as his “coach.”

One photo shows the man wearing the same blue jacket he was wearing at the marathon, flashing the peace sign, and walking on a track. Another shows him holding two trophies and wearing a medal in front of a banner for the Momentum Athletic Club under the quote by Ralph Waldo Emerson, “Nothing great was ever achieved without enthusiasm.” A third photograph shows the young man standing in front of a blue backdrop at the Boston Marathon, posing for the camera and holding the bag now seen on the cover of the New York Post.

The Smoking Gun also identified a post the young man wrote, about his love of running, on a website about college athletic recruitment tips. “I been doing this since I was 12 years and I enjoy it,” he wrote. “I feel great when I run with clubs more than when I run with school because clubs take it serious and the coaches have more techniques to teach.” He later added: “My dream is to get to the level where everybody who works hard deserve [sic] and I want to say thank you to the people who supported me in this.”

Splashing more cold water on the Post and the cybersleuths was CBS News's John Miller, a former FBI assistant director, who took to CBS’s This Morning to speculate that the FBI got these photos from the Internet, then sent them around as a “Does anybody know these people?”–type inquiry, and that the Post then came across the images. “I’m suggesting it’s not certain at all that that is the same individual the FBI is looking at from the security cameras they’ve downloaded,” Miller said.

Unless it’s an elaborate alibi, the young man was himself affected by the attacks. On Monday he posted that he was “going to Boston hospital.” One of his “best friends” got injured, but he didn’t know how he was going to get there.

But all this evidence has vanished.

An hour after he first posted about going to “court,” the student wrote briefly on his page that he was “back home” and “everything is fake, may god be with me.” He then deleted—or set to private—his recent posts, changed his name, and locked down his Facebook security settings to ensure only friends could comment on his updates. He proclaimed his innocence to ABC News on Thursday, too.

It was too late.

The Post cover was already to press, and by Thursday morning, the two men were the focus of worldwide attention. Parrying a storm of criticism for running the photographs, Post editor Col Allan issued a statement Thursday afternoon, standing by the cover and claiming that the paper didn’t call the men “suspects.”

Back on Reddit, users are doing their best to cover for the site’s apparent missteps, now blaming “the media” for the witch hunt they created and removing links to the threads that first showed their pictures.

“This is irresponsible journalism at its worst,” wrote Rather_Confused, one of the Subreddit’s moderators. “Authorities didn’t circulate those photos, they were up on 4chan and r/findbostonbombers and were never meant to be widely circulated as ‘suspects.’ The fact the NYPost printed this doesn’t surprise me, but it certainly does disgust me.”

Others are calling for the whole operation to be shut down. “Close this f**kin subreddit please. You have done more harm than good and you are not going to help the FBI in anyway to catch the bomber(s),” one Redditor posted in a thread Thursday morning. “Please close this subreddit and let the FBI do their jobs without anymore interference.”