The Boston bombers and the cycle of vengeancce

The bombing of the Boston Marathon in April 2013 was a heinous crime. Three people died, hundreds were injured, and a policeman was killed in a shootout with the perpetrators. One of the two brothers responsible for the attack died from the shootout. The other, 21-year old immigrant Dzhokhar Tsarnaev, has been convicted of all charges against him and sentenced to death by lethal injection.

Why