As soon as two pressure cookers crammed with shrapnel killed three innocent bystanders and wounded scores more near the Boston Marathon's final stretch on Monday, the hunt for a terror suspect was on. Right now, police are combing through Watertown, Mass., in hopes of finding the second of two brothers from Chechnya suspected of carrying out the attack, but not before several knee-jerk, false alarms triggered by Reddit and an information-hungry media led to several other "suspects" being wrongly ID'd. How could this happen? Here, a rundown of the wrongfully accused:

1. "The Saudi national"

Age: 21

On Monday, in the immediate frenzy of the explosions, the New York Post boldly trumpeted that a "Saudi national who suffered shrapnel wounds" had been identified as "a suspect in the Boston Marathon bombing." Yes, a 21-year-old English student who was, in fact, injured by the very bombing he was suspected of plotting.

Talking Points Memo quickly debunked the The Post's claim that the person being questioned was a suspect. "Honestly, I don't know where they're getting their information from, but it didn't come from us," a Boston Police Department spokesperson told TPM. The young Saudi national was later revealed to be a witness, not a suspect. The Post never apologized.

"What made them suspect him?" asks Amy Davidson at The New Yorker. "He was running — so was everyone."

The police reportedly thought he smelled like explosives; his wounds might have suggested why. He said something about thinking there would be a second bomb — as there was, and often is, to target responders. If that was the reason he gave for running, it was a sensible one. He asked if anyone was dead — a question people were screaming. And he was from Saudi Arabia, which is around where the logic stops. Was it just the way he looked, or did he, in the chaos, maybe call for God with a name that someone found strange? [The New Yorker]

2. A high school track star

Age: 17

The intrepid online sleuths at Reddit had nothing but good intentions when they created a subforum to crowdsource information on the criminals behind the Boston attacks. As my colleague Keith Wagstaff wrote, "the /r/findbostonbombers subreddit is a mostly harmless rabbit hole of marked photos and amateur conjecture," but "the problem starts when theories go viral or are adopted by the media."

Case in point: This photo of a "suspect" standing next to another man implicated for not doing much more than wearing a backpack. Worse still, the New York Post shamelessly plastered that same image on its front page the next day, along with the guilt-drenched cover line "BAG MEN."

The young man in question turned out to be 17-year-old Salah Eddin Barhoum, a high school track star who moved to the U.S. four years ago from Morocco. His dream is to one day run in the Olympics.

"I'm not a terrorist… I was just watching the marathon," Salah told the Daily Mail. "I was terrified. I have never been in trouble, and I feared for my security."

At 1.30am I called a friend to take me to the state police — I walked into the lobby and told them I thought I was wanted by the FBI. They didn't know what to make of it.

I had my papers with me and I gave them my Social Security number so they could check me out.

They didn't even take me into a private room. They made some calls, then said I was free to go. [Daily Mail]

The internet, ladies and gentleman.

3. A missing student

Age: 22

"Thousands of Reddit users and 4chan people spent the days after the bombing combing through every available photo and frame of video of the site of the bombings, searching for the perpetrators," says Alex Pareene at Salon. "And they found a bunch of guys with backpacks."

One of them was believed to be Sunil Tripathi, a Brown University student from Pennsylvania who has been missing since March 16. Tripathi allegedly left behind all his belongings, as well as a vague note that suggested a possible suicide. Says one of his friends:

Having known Sunil for years as a classmate, roommate, and friend, I can honestly say that he was one of the nicest individuals I've met at Brown. He has a great sense of humor and got along well with everyone. He loves to bike, play the sax, and talk about philosophy. We all hope that he is safe, wherever he is. [International Business Times]

"Who disappears — causing a well-publicized region-wide search that had already expanded beyond Providence to Boston — a month before carrying out a terrorist attack?" asks Pareene. "Wouldn't it be smarter to act normal as long as possible, and maybe not do something that gets your picture posted all over television and the Internet before you attempt to plant a bomb in an incredibly public venue?"

Some blogs still picked up the story and ran with it. Tripathi's name and picture were everywhere. A Facebook page, "Help Us Find Sunil Tripathi," was soon deleted by his family after it filled up with ugly (and false) accusations.

Hey, all who tweeted the name of a poor kid because you heard it on a scanner and further destroyed an already destroyed family? Go to hell. — Stephen Rodrick (@stephenrodrick) April 19, 2013

Tripathi's whereabouts are still unknown.

4. A mystery man

Age: Unknown

On Thursday night, gunshots rang through the MIT campus in what became a bloody shoot-out after the two actual suspects robbed a 7-Eleven. Twenty-six-year-old police officer Sean Collier was left dead. And somehow, a man named Michael Mulugeta was (falsely) reported to be involved.

The confusion came when hacker group Anonymous posted a tweet: "Police on scanner identify the names of #BostonMarathon suspects in gunfight, Suspect 1: Mike Mulugeta. Suspect 2: Sunil Tripathi." It was retweeted nearly 3,200 times. It was also, well, wrong.

I was a crime reporter for almost 4 years. The police scanner is not a reliable source of some types of info -- including names of people. — Zach Lowe (@ZachLowe_NBA) April 19, 2013

It remains unclear who Mulugeta is — or if he even exists.

"The last thing we want to become are reporters for the fugitive," Clint Van Zandt, former FBI profiler and NBC criminal analyst, told NBC News. "That's what I think people who tweet and post have to be careful of in the extreme and worst-case scenario. Are they giving information that would give aid and comfort to a killer? If you ask yourself that question and the answer is no, then go ahead and post it."