Dzhokhar Tsarnaev sentenced to death for Boston Marathon bombings

Dzhokhar Tsarnaev was sentenced Friday to death by lethal injection for his role in the 2013 Boston Marathon bombings.

Tsarnaev and his brother, Tamerlan Tsarnaev, orchestrated an attack during the April 15, 2013 race using two homemade pressure-cooker bombs they detonated near the marathon's finish line on Boylston Street. Three people were killed during the bombings and 264 people were injured.

A Massachusetts Institute of Technology police officer was also killed by the Tsarnaev brothers three days after the bombings.

Tsarnaev was found guilty last month on all 30 charges he faced; 17 are punishable by death.

"Today, more than ever, we know that Boston is a city of hope, strength and resilience, that can overcome any challenge," Boston mayor Martin Walsh said, according to ABC News.

Tamerlan was killed in a shootout with police, during which Dzhokhar drove over his brother in a commandeered Mercedes while fleeing. The younger Tsarnaev brother was captured on April 19, 2013 after being found hiding in a boat in nearby Watertown, Mass.

A jury of seven women and five men all had to agree to the death penalty, otherwise the 21-year-old would be sentenced to life in prison.

Tsarnaev could be the United States' first terrorist executed in the post-9/11 era, however, a lengthy appeals process is expected to follow Friday's decision.

"This is Dzhokhar Tsarnaev - unconcerned, unrepentant and unchanged," prosecutor Nadine Pellegrin said, according to The Associated Press.