Boston Marathon Bomber to Die via Lethal Injection

The federal jury chose death by lethal injection for Tsarnaev, 21, over its only other option: life in prison without possibility of release.

After the verdict was announced, Carmen Ortiz, the U.S. attorney for the Massachusetts District, whose office prosecuted the case, said it was "just and fair".

"Our goal in trying this case was to ensure the jury had all of the information needed to reach a fair and just verdict. We believe we accomplished that goal and that the trial of this case has shown the world what a fair and impartial trial is like. Even in the wake of horror and tragedy we are not intimidated by acts of terror or radical ideals," she said.

"Today, the jury has spoken and Dzhokhar Tsarnaev will pay with his life for his crimes. Make no mistake– the defendant claimed to be acting on behalf of all Muslims– this was not a religious crime and is certainly doesn't reflect true Muslims beliefs. It was a political crime designed to intimidate and coerce the United States," Ortiz said.

150 witnesses recounted their experiences

The Boston bombing was one of the highest-profile attacks on U.S. soil since Sept. 11, 2001.

Tsarnaev, dressed in a dark sport coat and light-colored shirt stood quietly in court as the sentence was read, maintaining the stoic demeanor he had throughout most of the trial.

U.S. District Judge George O'Toole thanked Tsarnaev for his "composure and propriety."

During 10 weeks of testimony, the jury heard from about 150 witnesses, including people whose legs were torn off by the shrapnel-filled bombs.

It took the court clerk about 20 minutes on Friday to read out the 24-page verdict form, which covered the aggravating factors that prosecutors argued justified a death sentence and the mitigating factors the defense said suggested a life sentence, before he announced the actual sentence to the silent, packed courtroom.

The death penalty remains highly controversial in Massachusetts, which has not put anyone to death in almost 70 years and abolished capital punishment for state crimes in 1984. Tsarnaev was tried under federal law, which allows for lethal injection as a punishment.