On 15 April 2013, two bombs detonated at the Boston marathon, killing three people and injuring over 180. The authorities believe that the perpetrators were two brothers, Tamerlan and Dzhokhar Tsarnaev.
The Tsarnaev’s were born in Kyrgyzstan and were ethnically half Chechen and half Dagestani. By 2003, they had moved to the United States as asylum seekers, with Dzokhar eventually gaining American citizenship. They were living in Massachusetts. Boston has not previously been subject to a terrorist attack. However, the city and state of Massachusetts has a long history of ties to AQ and AQ-inspired militancy.
The full analysis, Historical Ties to Jihadism in Massachusetts, can be read here.