Two explosions near the finish line of the Boston Marathon on April 15 killed three people and wounded scores. Authorities launched a massive manhunt for two suspects seen on surveillance video. A look at the basics of the case:
Bombing suspect Dzhokhar Tsarnaev was hospitalized Saturday in serious but stable condition after having been found wounded and bloody the night before hiding in a boat parked behind a home in Watertown, a Boston suburb authorities had shut down to conduct house-by-house searches.
U.S. officials said a special interrogation team for high-value suspects would question Tsarnaev without reading him his Miranda rights, invoking a rare public-safety exception triggered by the need to protect police and the public from immediate danger. The American Civil Liberties Union said it was concerned about that. It said the exception applies only when there's a continued threat to public safety and is "not an open-ended exception" to the Miranda rule, which guarantees a suspect the right to remain silent and the right to an attorney.
Federal public defenders in Massachusetts have agreed to represent Tsarnaev and said they expect to do so after he is charged.
The FBI said a foreign government told it in early 2011 about information that Dzhokhar Tsarnaev's older brother, Tamerlan Tsarnaev, was a follower of radical Islam.
According to the FBI, the foreign government said Tamerlan Tsarnaev had changed drastically since 2010 as he prepared to leave the United States to join unspecified underground groups. The FBI says it interviewed him and relatives and didn't find any terrorism activity.
HOW THE SITUATION UNFOLDED
Surveillance tape late Thursday showed Dzhokhar Tsarnaev, Suspect No. 2, at a gas station. The two suspects fatally shot a university police officer, authorities say. They carjacked a man, released him and got involved in a chase with police that resulted in explosives being thrown from their car and an exchange of gunfire, authorities say. Tamerlan Tsarnaev, Suspect No. 1, was wounded and died later at a hospital.
After the death of one suspect and the capture of the other, people in Boston and its western suburbs thanked police, cheered, applauded and set off fireworks. Later, they gathered in silence near the site of the bombings to remember the victims. Some cried. Some wrapped themselves in American flags.
"Now I feel a little safer," Boston resident Beth Lloyd-Jones said.
Law enforcement officials and family members have identified the brothers as ethnic Chechens who had lived in Dagestan, in southern Russia. The brothers had been in the United States for about a decade and lived near Boston, an uncle said. Dzhokhar Tsarnaev, whose father has called him a "true angel," is a 19-year-old student at the University of Massachusetts at Dartmouth. Tamerlan Tsarnaev was a 26-year-old boxer. Their uncle Ruslan Tsarni called them "losers."
THE MARATHON EXPLOSIONS
Two bombs exploded about 10 seconds and 100 yards apart in Boston's Copley Square, near the finish line of the marathon. An 8-year-old boy, a 29-year-old woman and a 23-year-old graduate student from China were killed, and more than 180 people were wounded. The explosions occurred about four hours into the race and two hours after the winners had crossed the finish line, but thousands of runners were still on the course.
Authorities have said they believe the bombs used were fashioned out of ordinary kitchen pressure cookers packed with explosives, nails, ball bearings and metal shards. They say the bombs were hidden in duffel bags and left on the ground.