An 'angel' turned armed terrorist
Dzhokhar Tsarnaev, then a senior at a prestigious school, was awarded a 2,500 dollar (£1,640) scholarship in May 2011 from the city of Cambridge, Massachusetts, to pursue higher education. Now the 19-year-old is on the run, described as "armed and dangerous" and suspected of the Boston Marathon bombing.
Two brothers from the Russian region of Dagestan near Chechnya, one now dead, one alive and at large. After hours of only grainy images of two men in baseball caps to go on, a portrait quickly emerged of the young men suspected in the attack.
Tsarnaev and his older brother, Tamerlan, who was killed during a violent police chase, had been living together in Cambridge, outside Boston.
An uncle, Ruslan Tsarni, who lives in a Washington suburb, said the men lived together and had been in the United States for about a decade. They came from a Russian region that has been plagued by an Islamic insurgency related to separatist wars.
The suspects' father said his younger son was a second-year medical student and "a true angel". "My son is a true angel," Anzor Tsarnaev told The Associated Press by telephone from the Russian city of Makhachkala. "Dzhokhar is a second-year medical student in the US. He is such an intelligent boy. We expected him to come on holidays here."
Dzhokhar Tsarnaev's page on the Russian social networking site Vkontakte says he attended Cambridge Rindge and Latin School, graduating in 2011, the year he won the scholarship. It was celebrated with a reception at City Hall, according to a news release issued at the time.
Before moving to the United States, Dzhokhar Tsarnaev attended School No 1 in Makhachkala, the capital of Dagestan, a predominantly Muslim republic in Russia's North Caucasus that has become an epicentre of the Islamic insurgency that spilled over from Chechnya. The principal of School No 1, Irina Bandurina, told the AP that Tsarnaev left for the US in March 2002.
On the site, he describes himself as speaking Chechen as well as English and Russian. His world view is described as "Islam" and he says his personal goal is "career and money".
Tsarnaev appeared in the video released by authorities, identified as Suspect Number 2, walking down a pavement, unnoticed by marathon spectators. He followed Tamerlan, walking about 10ft behind him. He wore what appeared to be a grey hoodie under a dark jacket and pants and a white baseball cap facing backward and pulled down.
Tamerlan was stockier, in khaki trousers, a light T-shirt and a dark jacket. The brim of his baseball cap faced forward and he may have been wearing sunglasses. According to the website spotcrime.com, Tamerlan was arrested for domestic violence in July 2009, after assaulting his girlfriend.