frontier reads“The Brothers” is not only about the Tsarnaev brothers and their lives leading up to committing the Boston Marathon bombings on April 15, 2013. The book, by journalist Masha Gessen, is a captivating, mind-expanding look at how America defines and responds to terrorism, and how that shaped the brothers’ experiences in the country.

Before being sentenced to death last year, Dzhokhar Tsarnaev confessed that he and his brother, Tamerlan Tsarnaev, executed the bombings. I picked up the book because TIME Magazine named it one of the best books of 2015, and I thought it might be a better attempt at answering, “Why?”

It was.

Gessen begins with the Tsarnaev family history, which, for the brothers, includes growing up in war-torn Chechnya. The family sought asylum in the United States, arriving a few months after September 11, 2001. To an immigrant, Gessen says, America feels like the mood in the present moment, and in that moment, it was fear.

The Tsarnaevs came to America to flee terror in Chechnya. Gessen cites two major acts of terrorism that killed more than 100 people in Chechnya in 2002. The incidents received almost no media coverage or political action in the United States but were momentous for the Tsarnaev family.

In the book, Gessen describes how unfair it can be to be an immigrant:

“You never talk about the pain of dislocation. You do not describe the way color drains out of everyday life when nothing is familiar, how the texture of living seems to disappear.”

Allison Harris is a reporter at Channel 6 in Tulsa. She reviewed

Allison Harris is a reporter at KOTV Channel 6 in Tulsa. She reviewed “The Brothers” by Masha Gessen. The book tells the story of the Boston Marathon bombers, Dzhokhar and Tamerlan Tsarnaev.

Through this frame, she tells the story of the Tsarnaevs’ attempt to acclimate. Gessen describes the parents as wanting to do anything to make their kids perfect, anything to give them a good education. She describes Dzhokhar’s role as the sweet kid, and Tamerlan as the tall, strong older brother who could have had a career in mixed marital arts.

It’s a devastating story of the American Dream gone terribly wrong.

The details are, at times, exhausting, but important to the overall portrait of the brothers’ lives, like Dzhokhar’s fear of fireworks, which he seems to overcome before the bombings. As a reader, you can sense the enormous amount of work Gessen has done, traveling across the world to talk to people who interacted with the Tsarnaev family — even those who seem peripheral to their lives.

As the brothers grow older in America, Dzhokhar lives a life similar to many American students: going to school, playing FIFA video games with friends and smoking, sometimes dealing, pot.

Tamerlan is the more serious of the two, and things take a turn for the worse for him and the Tsarnaev family by 2010. Gessen documents what you assume, as a reader, to be Tamerlan’s downward spiral. He becomes a drug dealer and he becomes fascinated with researching American conspiracy theories. He travels to Makhachkala, the capital city of Dagestan in Russia, where he attends a mosque and studies the Quran.

Halfway through the book, Gessen dives into the events the day of, and days after, the Boston Marathon bombings. Here, the book becomes more about the criminal justice system and how the FBI performed its investigation.

Surprisingly, the second half of the book is less about the brothers and more about people who came into their lives and were persecuted and prosecuted because of that interaction.

Gessen tells the less-known story of Dzhokhar’s three college friends, who say they were in shock seeing Dzhokhar’s picture on the news, named as a suspect in the bombings. The friends went to Dzhokhar’s dorm room to investigate, found a backpack with marijuana and firework shells inside and dumped it. The friends said they were fearful police would find the marijuana and they’d get in trouble, but police thought they were part of the plot. The friends are followed, interrogated and jailed, some spending days in solitary confinement, each ending up in extensive litigation battles barely covered by media.

Gessen shares other stories of Tsarnaev family friends, also immigrants, who were murdered, killed by a police officer, put under “overt surveillance” and charged with obstructing justice by destroying evidence.

In the end, Gessen dispels ?? the one thing I was searching for the whole time I was reading the book — who, or what, radicalized Tamerlan and Dzokhar Tsarnaev.

Tamerlan’s friend and Gessen agree that Tamerlan and Dzhokhar’s motivation could have been as simple as they objected to U.S. foreign policy. Gessen writes that Americans focus on the theory of radicalization, but research shows not all terrorists have strong political or ideological beliefs.

She offers several more ideas as to why the brothers might have committed the bombings, but, ultimately, the question that eludes Gessen is the question that haunts many Americans: How did seemingly normal brothers cause such carnage?

Gessen is able to depict the brothers, the monsters, as people. People who had friends and futures before committing one of the worst terrorist attacks in United States history. Although questions remain, she provides a much more in-depth look at their lives, and terrorism in America.