A week of terror

Dzhokhar Tsarnaev's arrest the night of Friday, April 19, 2013 ended a wrenching five days in Boston, which began when two bombs exploded near the finish line of the Boston Marathon.

Monday, April 15, 2013

Around 2:49 p.m.: About four hours into the marathon, two explosions erupted, about a block apart, killing three people and injuring more than 170, many of them critically.

Second blast Seconds later

Explosion at the finish line 2:49 p.m.

Immediately following the blasts, emergency workers, volunteers and bystanders rushed to help victims. A medical tent set up to care for runners near the finish line was converted into a makeshift trauma clinic.

Investigation Monday - Wednesday

The FBI said the bombs used in the attack seemed to be pressure cooker
devices filled with nails and other shrapnel, and that both explosives
were placed in a nylon bag or backpack.

Pressure cooker lid

Backpack remains

Suspects appeared on
surveillance footage here

Thursday night
Suspect spotted in runner's photo

After officials released surveillance video of the suspects, a Jacksonville businessman realized he had taken a picture of Dzhokhar Tsarnaev walking away from the scene.

Thursday

FBI releases surveillance footage 5:10 p.m.

On Thursday, the FBI released video and photos of two suspects wearing hats and carrying backpacks. The suspects are seen turning from Gloucester Street onto Boylston Street and walking toward the finish line. Tamerlan Tsarnaev is in front and wearing a dark hat. His younger brother, Dzhokhar, is wearing a white cap.

The manhunt

Thursday night to Friday night

    Friday evening

    The dramatic end to the hunt for Dzhokar Tsarnaev came shortly after police lifted the day-long lockdown, when a Watertown resident noticed that the tarp covering his boat was untied. A police helicopter equipped with thermographic cameras confirms that there is a warm body hidden inside the boat.

    Once police confirmed Tsarnaev was in the boat, they pounded the boat with flashbangs, a powerful concussive force, to see if he would react; he barely did.

    How a flashbang works

    These hand thrown non-lethal one time use devices are used in forced entry scenarios, hostage rescue and crowd control operations. When detonated, the grenade delivers a loud bang and bright flash sufficient to temporarily confuse, disorient and momentarily distract the target subject.

    Thermal image of suspect: body heat is visualized as darker shades of gray.

    Finally, a robot dragged back the cover. Police had no idea whether he had weapons or explosives with him, so they repeatedly told him to stand up and lift his shirt to show he wasn't wearing a device. He eventually did and the SWAT team pulled him out. Local police cuffed the suspect, who was then taken by ambulance for medical attention. Twenty-seven hours after the FBI released the surveillance video, Boston Mayor Tom Menino said, "I am so proud of all our first responders. Thanks to them, the people of Boston will sleep well tonight."

    Robot drags back the cover.

    Tsarnaev is searched by law enforcement officers.