Sentencing phase: Tsarnaev faces life or death

Prosecutor Nadine Pellegrini started laying out her case for the death penalty against Dzokhar Tsarnaev in a federal court in Boston on Tuesday, saying the "unbearable, indescribable, inexcusable, senseless" attacks proved that Tsarnaev and his beliefs were "destined to become America's worst nightmare."

Victims and survivors of the attacks on the 2013 Boston Marathon were called to testify against Tsarnaev, who was convicted on all 30 charges against him earlier this month. Several of those charges, including fatally shooting a university campus police officer, can carry the death penalty.

Double amputee Celeste Corcoran was the first witness, telling the 12-person jury that it was an "idyllic" day when she and her family gathered to cheer on her sister at the finish line.

"I saw blood. I saw a lot of blood," she said. "When the first responders moved me, it was the first time I had breath enough to scream in agony." Corcoran also described the terror and fear for her young daughter, herself severely injured in the blast.

Three people were killed and 264 injured in the explosion, the worst terror attack on US soil since September 11, 2001. Another witness, who was 18 at the time of the bombing, described the serious leg injuries she sustained and said that when the bombs went off, there followed "a complete, utter chilling silence," and then "chaos."

The sentencing phase of the trial also began a day after some 30,000 people raced through the streets of Boston in city's 2015 marathon.

Big fish, or little brother?

The first segment of the trial was devoted only to determining guilt or innocence on the 30 charges, with a sentencing phase to follow. In part, this was because of the defense team's frank admission of Tsarnaev's involvement in the bombing. Defense attorney Judy Clark notoriously opened her case by pointing at her client and declaring: "It was him."

Thus far, the defense's case had been broadly based on portraying Tsarnaev as a willing follower of his elder brother, Tamerlan. Tamerlan was killed after a shootout with police; Dzokhar escaped in a car, running his brother over in the process. Tsarnaev was later found, severely wounded, hiding in a boat in a private garden, having scrawled a note seeming to blame US military actions in Muslim countries for his actions.

A US citizen of Chechen descent, Dzokhar Tsarnaev was 19 at the time of the attack. His lawyer, Clarke, had previously argued that the homemade pipe bombs and pressure-cooker bombs were made by Tamerlan, at one point saying: "Tamerlan led and Dzokhar followed."

On Tuesday, however, prosecutor Pellegrini described Tsarnaev as "unconcerned, unrepentant and unchanged," showing the jury a photograph of him in a prison jump suit raising his middle finger at the camera.

msh/cmk (AFP, AP, Reuters)