But the group has long terrorized residents of northern Nigeria -- especially Christians, according to one survivor of an attack.
Habila Adamu, a resident of northern Nigeria, survived a mass killing of Christians by Boko Haram two years ago and came to the United States to share his story last year.
He recalled how gunman bearing AK-47s went around his neighborhood shooting and killing Christians who refused to accept Islam.
"They asked me, 'Habila, are you ready to die as a Christian?'" Adamu recalled during his testimony in Congress last November. They were the last words Boko Haram gunman spoke to him before they shot him through the head.
"On November 28, 2012, gunmen came to my home at around 11 p.m. and confronted me with my family. I thought they were soldiers on patrol, and when they opened the door, I was shocked to see that they were wearing robes and masks," he said.
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"The gunmen ordered me to come out with my family. And when I came out, they ordered my family to go back, and my wife begged them not to harm me. They said she should go back, because they were here to do the work of Allah. When I heard that, I knew that they were here to kill me."
Adamu said that his wife brought money from inside the house and begged the men not to kill him. They took the money and the couple's cell phones, and then barged into the home with even more men with AK-47s.
The men questioned Adamu, asking him whether he was a member of the Nigeria police, the military, or the state security services.
When Adamu said he was a businessman, they asked him about his religion.
"I said I am a Christian. They asked me why are we preaching the message of Mohammed to you and you refuse to accept Islam," Adamu testified.
He explained to the men that he believed he was preaching the word of God for his Christian faith.
"Then they asked me, 'Habila, are you ready to die as a Christian?' I told them, 'I am ready to die as a Christian.' For the second time, they asked me, 'Are you ready to die as a Christian?' and I told them, 'I am ready.'"
As he spoke the words a second time, the men shot him through the nose and Adamu fell to the ground. They kicked him and, thinking he was dead, yelled out "Allahu akbar," meaning "God is great."
As his wife was crying out the men left, and Adamu told his wife he was alive.