Fall 2006, Tamerlan Tsarnaev enrolled as a part-time accounting student at Bunker Hill Community College in Boston. He took classes for only three semesters — fall 2006, spring 2007 and fall 2008. "He wasn't even close" to getting a degree, said Patricia Brady, a spokeswoman for the college.
Around 2007, Dzhokhar Tsarnaev enrolled in Cambridge Rindge & Latin School, a public school in Cambridge, Massachusetts, that counts actors Matt Damon and Ben Affleck, poet e.e. cummings and basketball star Patrick Ewing among its alumni.
May 2009, Tamerlan Tsarnaev competed in the Golden Gloves National Tournament of Champions in Salt Lake City, Utah. He lost his first bout.
July 2009, Tamerlan Tsarnaev was arrested after a woman identified as his girlfriend accused him of domestic abuse, a charge that was dismissed at a jury trial in 2010.
Sometime in 2009, Ruslan Tsarni, an uncle of the brothers, told CNN he first noticed a change in Tamerlan Tsarnaev's religious views. He said the radicalization of his nephew happened "in the streets of Cambridge."
2009 or 2010, Tamerlan married Katherine Russell, whose family lives in an upper middle-class neighborhood in North Kingstown, Rhode Island. Her father is licensed as an emergency room physician. The couple have a child named Zahara.
2010, The Comment, the graduate student magazine of Boston University's College of Communications, ran a photo spread of Tamerlan Tsarnaev training at a boxing gym. He told the magazine "I don't have a single American friend. I don't understand them." He also said he abstained from drinking and smoking: "God said no alcohol."
February 2010, Tamerlan Tsarnaev won the Rocky Marciano Trophy, an honor awarded to the heavyweight champion of New England.
Early 2011, Russia's Federal Security Service, or FSB, asked the FBI to investigate Tamerlan Tsarnaev out of concern that he had embraced radical Islam and was going to travel to Russia to join unspecified radical groups. The FBI interviewed Tsarnaev and his family members and examined his travel and Internet records.
Bombing suspects Tamerlan Tsarnaev, left, and Dzhokhar Tsarnaev, right. (The Lowell Sun & Robin Young / AP)
Spring 2011, Dzhokhar Tsarnaev graduated from Cambridge Rindge & Latin School. He was an all-star member of the wrestling team and won a $2,500 scholarship from the City of Cambridge. Friends and acquaintances remembered him as cheerful and wanting to fit in, an "all-American kid in every measurable sense of the word."
Summer 2011, The FBI informed the FSB that it "did not find any terrorism activity, domestic or foreign" in its investigation into Tamerlan Tsarnaev. A subsequent FBI request for more cooperation and clarifying information from the FSB went unanswered. Both of Tsarnaev's parents told Russian television networks that the suspected bomber believed he was under continued FBI surveillance.
September 2011, Three men, including one who was a close friend of Tamerlan Tsarnaev, were fatally stabbed in the neck in an apartment in Waltham, Massachusetts. Authorities are investigating whether Tsarnaev had any connection to the unsolved triple homicide. At the time of the stabbings, the local district attorney's office said it appeared that the victims knew their assailants and that the attacks were not random.
Fall 2011, Dzhokhar Tsarnaev transferred to the University of Massachusetts-Dartmouth from the University of Massachusetts Boston. His classmates remembered him as a friendly, pot-smoking student who took easy classes and got middling grades. He brushed off invitations to join the Muslim Student Association on campus.
January 2012, Tamerlan Tsarnaev departed the United States for Russia for a six-month visit. For at least a month in the summer, Tsarnaev helped his father renovate his first-floor apartment next door to a dental office in Makhachkala, a city in Dagestan on the Caspian Sea. It was unclear what else he did while he was in Russia, whether he traveled elsewhere and whether he met with any members of radical groups. "They say he was a fanatic. I didn't see that," a neighbor of Tsarnaev's father said.
September 2012, Dzhokhar Tsarnaev was sworn in as a naturalized U.S. citizen. Tamerlan Tsarnaev applies for U.S. citizenship. Because of the previous FBI inquiry into his activities and the prior domestic abuse complaint against him, Tsarnaev's application prompted "additional investigation." He was still under consideration for citizenship at the time of the April 15 bombing.
November 2012, Tamerlan Tsarnaev interrupted a sermon at the mosque of the Islamic Society of Boston to object to a preacher's call for Muslims to celebrate holidays like July 4th and Thanksgiving just like the birthday of the Prophet Muhammad.
January 18, 2013, Tamerlan Tsarnaev again interrupted a sermon at the same mosque to object to a preacher who called civil rights leader Dr. Martin Luther King, Jr. a great person.
April 15, 2013, Two bombs went off at the crowded finish line of Boston's famous marathon race, killing three people and wounding at least 200. Ten of the injured lost limbs.