Boston Marathon bomb Tsarnaev trial: what you need to know

Tsarnaev, 21, is charged with killing three people and injuring 264 with two homemade pressure-cooker bombs that ripped through the crowd at the race’s finish line on 15 April, 2013. He could be sentenced to death if convicted of charges that also include fatally shooting a police officer.

How did events unfold?

On 15 April 2013 two large explosions near the finish line of the Boston marathon killed three people and injured an estimated 264 others. On 18 April, the FBI released photographs and CCTV footage of two suspects Chechen brothers Dzhokhar and Tamerlan Tsarnaev.

Tamerlan died during a shootout with police after the attack in April, and Dzhokhar was found the next day, hiding inside a boat, after a massive manhunt.

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The authorities allege that the two brothers orchestrated the attack, hijacked a car and killed a police officer while they were on the run.

Dzhokhar was charged on 22 April with “using and conspiring to use a weapon of mass destruction resulting in death” and with “malicious destruction of property resulting in death.”

How many people were killed?

The bombing killed restaurant manager Krystle Campbell, 29; graduate student Lingzi Lu, 23, and Martin Richard, 8. Massachusetts Institute of Technology police officer Sean Collier, 27, was fatally shot three days later.

Who is Dzhokhar Tsarnaev?

Dzhokhar Tsarnaev was born in in Kyrgyzstan 22 July 1993. As a child, he immigrated with his family to Russia before moving to the United Stated under political asylum aged eight. He is half Chechen.Before moving to the United States, Dzhokhar attended a school in Makhachkala, the capital of Dagestan, a predominantly Muslim republic in Russia’s North Caucasus. The area has become an epicentre of the Islamic insurgency that spilled over from Chechnya.

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As a high-school wrestler, Dzhokhar was named as student athlete of the month for February 2011. An amateur boxer, Tamerlan weighed 196 pounds and regularly trained at a local mixed martial arts centre in Allston, a Boston suburb. On the Russian-language social-networking site VK, Dzhokhar lists his “world view” as “Islam” and his personal priorities as “career and money”.

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He posted links to Islamic websites, links to videos of fighters in the Syrian civil war, and links to pages advocating independence for Chechnya. He became a US citizen on 11 September, 2012. In April 2013, post-bombings, his mother Zubaedat Tsarnaeva spoke exclusively to Channel 4 News – where she defended her sons.

In July 2013 he was controversially featured on the front cover of Rolling Stone.

And what does the defence say?

Defence attorneys in the US aim to portray Tsarnaev as having been under the spell of his 26-year-old brother, Tamerlan, who they contend was the mastermind behind the attack.

What could the sentence be?

A panel of 10 women and eight men, all white, were chosen to hear Tsarnaev’s trial and, if they find him guilty, to determine whether to sentence him to death or life in prison without the possibility of parole in proceedings expected to last into June. Tsarnaev has pleaded not guilty to all charges in a 30-count indictment.