Susan Zalkind covered the Boston bombing for Boston Magazine and “This American Life.” At the Boston Marathon this month, its host city will mark one year since Tamerlan and Dzhokhar Tsarnaev allegedly planted two bombs at the finish line , killing three and injuring hundreds more. As the nation commemorates the resilience of runners, victims, first responders and residents, many questions surrounding this tragedy remain unresolved. Let’s tackle some persistent misconceptions.

1. The bombing couldn’t have been prevented.

Three months after the bombing, then-FBI Director Robert S. Mueller III said the bureau’s failure to share information about the elder Tsarnaev wasn’t important. “Even if [procedures] had been fixed prior to the Boston bombing, I do not think it would have stopped it,” he told the House Judiciary Committee.

This is hard to believe. In 2011, Russian officials alerted the FBI to Tamerlan’s growing radicalism and asked it to monitor his travel. Though the FBI interviewed him, it didn’t stop him from traveling. A Boston agent at the Joint Terrorism Task Force received an alert from the Department of Homeland Security about Tamerlan’s flights to and from Dagestan in 2012, but Tamerlan wasn’t questioned at the airport. A similar tip Russia shared with the CIA later that year was overlooked because of a spelling error.

Local police failed, too. After the bombing, Tamerlan was implicated in a triple murder committed in Waltham, Mass., on Sept. 11, 2011. (Erik Weissman, one of the victims, was my friend.) The day the bodies were found, a Middlesex district attorney said that “it does look like the assailants and the decedents did know each other”; soon after the marathon attack, the office said that its investigation into the killings had been “thorough” and “far-reaching.” Yet, though Tamerlan was one victim’s sparring partner and several friends gave police his name, officers never followed up.

2. Crowdsourcing helped the investigation.

In an interview with CBS, Richard DesLauriers, the former head of the Boston FBI, stood by the decision to release photos of the alleged bombers. “These individuals could have had more bombs and could have set those bombs off,” he said.

But when the FBI released the grainy images of the two suspects, chaos ensued. A few hours after their pictures appeared, the Tsarnaevs allegedly shot a Massachusetts Institute of Technology police officer to death, hijacked a car and threw homemade grenades at police. The next day, as the younger Tsarnaev hid in a boat, the city was locked down .

Had the FBI — which, remember, interviewed Tamerlan in 2011 — done its homework, it wouldn’t have needed to ask the public for help. After the Monday bombing, the Tsarnaevs hung around town. Dzhokhar spent Wednesday at his dorm at the University of Massachusetts at Dartmouth tweeting Eminem lyrics, going to the gym and hanging out at a party. The brothers could have been quietly arrested.

Even before the photos were released, would-be sleuths on Reddit.com undertook their own misguided investigation, scrutinizing images of the marathon crowd. “Find people carrying black bags,” wrote one unnamed moderator on the Web site. “If they look suspicious, then post them.” Some wrongly suspected a 22-year-old Brown University student who had been missing for a month. Commenters trolled his missing-person Facebook page, and news vans showed up at his family’s home, but he was found dead in a river one week later. Reddit had to apologize.

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3. The Tsarnaevs acted like other homegrown terrorists.

Former New York police intelligence analyst Mitchell Silber says the Tsarnaevs would not have eluded authorities had Boston adopted New York’s controversial surveillance program that monitors Muslims . He noted common warning signs of radicalization, saying, “These individuals gave up their old habits, they gave up their old friends,” Silber told CNN. Tamerlan “gave up boxing because that was considered a secular activity.”

But according to associates I interviewed, Tamerlan still boxed with his old non-Muslim friends after his trip to Dagestan. Dzhokhar, meanwhile, exhibited no warning signs at all. In fact, three days before the bombing, Tamerlan and Dzhokhar were at a mixed-martial-arts gym. “All you need is boxing,” Tamerlan told one man I interviewed who saw him there that day.

In a 2011 report, Faiza Patel of New York University’s Brennan Center for Justice argued against the idea that “the path to terrorism has a fixed trajectory.” We can’t fight terrorism with information about workout habits.

4. The FBI’s shooting of Tamerlan’s friend was justified.

In May 2013, Ibragim Todashev, who may have committed the Waltham murders with Tamerlan in 2011, was shot to death after attacking an FBI agent during questioning in Florida. The FBI, the Justice Department and a Florida prosecutor later ruled that the agent had acted appropriately. But while the agent may have had to shoot Todashev, neither he nor the two Massachusetts state troopers with him should have interviewed a professional fighter with a hair-trigger temper in his own apartment for five hours.

“You don’t have to work on the bad guys’ schedule,” former FBI agent Michael German told me, saying the interview should have been conducted in a more secure location. “What detectives and FBI agents have is time.”

Once in Todashev’s home, his questioners didn’t behave responsibly. They didn’t bring enough batteries for their recording devices, so they used their phones — until a state trooper in the room started texting. Such recklessness put the officers and Todashev — who was shot seven times, including twice in the back, after he threw a coffee table at the FBI agent — at risk. Worse, it prevented the public from understanding Tamerlan’s affiliations.

5. Massachusetts wants Dzhokhar to get the death penalty.

Attorney General Eric H. Holder Jr. is seeking capital punishment for the alleged Boston bomber, and few Massachusetts politicians have spoken out against his ruling. Sen. Elizabeth Warren, Sen. Ed Markey, state Attorney General Martha Coakley and Boston Mayor Marty Walsh support Holder’s decision, while Gov. Deval Patrick dodged the topic. “One way or another,” he said, “Tsarnaev will die in prison.”

But this doesn’t reflect public sentiment — or the sentiment of some politicians who are remaining silent.

According to a Boston Globe poll, 57 percent of Massachusetts residents are in favor of Dzhokhar receiving a life sentence rather than death, and the paper has penned editorials against the death penalty in this case. Patrick, Coakley and Walsh were all elected on anti-death-penalty platforms. Even Holder says he is personally opposed to capital punishment.

Meanwhile, no one has been executed in Massachusetts since 1947, and capital punishment was found unconstitutional in the state in 1984. When future presidential candidate Mitt Romney tried to reinstate the death penalty in 2005 as governor, he failed.

susanzalkind@gmail.com

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