Eventually, though, the driver is able to escape his captors by running from them into a gas station convenience store.
Thanks in large part to information from the hostage, authorities track down the suspects. A chase ensues, during which the suspects toss explosives and exchange gunfire with police.
Tamerlan Tsarnaev dies after the gunfight, while his brother eludes authorities.
Daytime: Boston and surrounding communities are put on lockdown -- with schools closed, public transit halted and people ordered off the streets -- as authorities hunt for the surviving suspect.
Sometime that afternoon, some 60 miles south in New Bedford, a garbage truck clears the dumpster outside Kadyrbayev and Tazhayakov's apartment. The dumpster had contained Tsarnaev's tossed backpack.
6 p.m. to 9 p.m.: After the lockdown is lifted, a resident goes outside to check on his boat parked in the backyard and notices blood inside. His tip leads to a large-scale law enforcement effort that culminates with the capture of Dzhokhar Tsarnaev.
When the suspect is found, he has visible injuries including apparent gunshot wounds to his head, neck and legs and hand. His wounds are treated, and he is transported by ambulance to Boston's Beth Israel Deaconness Medical Center.
April 19 and 20
Investigators interview Dias Kadyrbayev over parts of two days. He discusses his relationship with Dzhokar Tsarnaev, whom he met when they both enrolled at the University of Massachusetts-Dartmouth in fall 2011. They hung out in and outside school, with Kadyrbayev noting that he'd repeatedly visited Tsarnaev's home in Cambridge and met his family members.
FBI agents questioned Kadyrbayev and Tazhayakov for about 10 hours on April 19, then they were taken into custody the next day, said Robert Stahl, Kadyrbayev's lawyer. They remained detained for several days on alleged visa violations.
The FBI searches Dzhokhar Tsarnaev's dorm room in Pine Dale Hall, on the campus of the University of Massachusetts-Dartmouth. Among other things, they seize BB's, "a large pyrotechnic," as well as a black jacket and white hat like those worn on Marathon day by the man referred by authorities to as "Bomber Two."
Law enforcement agents recover Tsarnaev's backpack at a New Bedford landfill. Inside, they find an assortment of fireworks, a jar of Vaseline, a homework assignment sheet from the University of Massachusetts-Dartmouth and other things.
Federal authorities announce charges against three of Dzhokhar Tsarnaev's friends.
Azamat Tazhayakov and Dias Kadyrbayev are charged with having willfully "conspired with each other to commit an act against the United States ... by knowingly destroying, concealing and covering up objects belonging to Dzhokhar Tsarnaev."
Phillipos is charged with having "knowingly and willfully (made) materially false statements to federal investigators."