some resources and links:
http://livewire.wcvb.com/Event/117th_Running_of_Boston_Marathon
http://www.telegraph.co.uk/news/worldnews/northamerica/usa/10002469/Boston-Marathon-bombs-live.html
http://dailycaller.com/2013/04/19/shooter-reported-on-mits-campus/
http://dailycaller.com/2013/04/19/police-converge-on-neighborhood-outside-boston/
http://www.myfoxboston.com/category/262392/boston-marathon
http://www1.whdh.com/video/7newslive
15.33 (10.33) The University of Massachusetts Darmouth has confirmed that one of the bombers went there. We believe it is Dzhokhar, whose father earlier said he was a second year medical student.
15.20 (10.20) Dzhokhar could be wearing an explosive vest, police fear, according to the Boston Globe.
15.18 (10.18) There are lots of reports about a train being stopped in Connecticut relating to this manhunt. But it's not clear if Dzhokhar is meant to be on this train or if there is a third suspect.
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UPDATE 10:17 a.m. ET NBC News reports 26-year-old Tamerlan Tsarnaev was found with an improvised explosive device on his body.
UPDATE 10:03 a.m. ET From the Boston Globe: The Tsarnaev family moved to Dagestan from Kyrgyzstan in 2001, a spokesman at a school the children attended told Russia Today [...] He arrived at our school in first grade and left in second, Irina Bandurina, the secretary at Makhachkalas School No.1, told RT. They arrived from Kyrgyzstan and departed to the US. Im telling you they lived here for a year. Not the whole year. They arrived at the school in 2001 and departed in March 2002
There were four of them two sisters and two brothers
Its written here that they are from Kyrgyzstan. They are Chechens.