Two explosions near the finish line of the Boston Marathon on April 15 killed three people and wounded more than 180 others. Authorities launched a massive manhunt for two suspects seen on surveillance video. A look at the basics of the case:
Bombing suspect Dzhokhar Tsarnaev remained hospitalized in serious but stable condition Sunday, two days after he was found wounded and bloody hiding in a boat parked behind a home in Watertown, a Boston suburb authorities had shut down to conduct house-by-house searches.
A defiant, festive mood prevailed at the London Marathon on Sunday as thousands of runners offered tributes to those killed and injured in Boston a week earlier. The race began after a moment of silence for the Boston victims, and many wore black armbands as a sign of solidarity. Police said they planned to add 40 percent more officers and extra surveillance as a precautionary measure.
At least 250 people gathered Saturday night in Watertown for a candlelight vigil for the victims of the Boston attacks. Attendees recited the Pledge of Allegiance and sang the national anthem, and some children released balloons into the air.
HOW THE SITUATION UNFOLDED
Surveillance tape late Thursday showed Dzhokhar Tsarnaev, Suspect No. 2, at a gas station. Authorities said the two suspects fatally shot a university police officer then carjacked a man and got involved in a chase with police that resulted in explosives being thrown from their car and an exchange of gunfire. 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 backpacks and left on the ground.