Story highlights Dzhokhar Tsarnaev was seen on campus, at party after marathon bombings

Younger brother was found hiding in boat after manhunt

Authorities sought brothers after analyzing photos from scene

Older brother died in shootout, was run over by Tsarnaev, police say

As the world hunted him, the younger brother suspected in the Boston Marathon bombings acted like any other college sophomore.

Dzhokhar Tsarnaev, 19, was on the campus of University of Massachusetts-Dartmouth every day after the attack until late Thursday, a university official told CNN. Tsarnaev attended classes and dorm parties and went to the gym while the rest of Boston came to a tense standstill.

A student at the school told The Boston Globe that she saw Tsarnaev at a party Wednesday night that was attended by some of his friends from intramural soccer.

"He was just relaxed," she said, asking the paper not to print her name.

Another UMass Dartmouth student said he talked about the bombing with Tsarnaev for several minutes Tuesday while they were working out at the gym. Tsarnaev seemed normal, perhaps a little tired, Zach Bettencourt told CNN.

Bettencourt said he told Tsarnaev something about the bombing, to the effect of, "You hear about this kind of thing happening in Iraq and Afghanistan, but not here."

"He was like, 'Yeah, tragedies happen like this all the time and it's sad,' " Bettencourt said, adding he had no inkling about anything suspicious with Tsarnaev, whom he described as a nice guy.

The days-long drama that gripped Boston -- and the world -- began when two homemade bombs made from pressure cookers exploded 12 seconds apart near the finish line of Monday's Boston Marathon. Three people were killed, and more than 170 wounded as nails, ball bearings, BBs and shards of broken glass were blasted through the viewing area.

Photos: Photos: Manhunt for Boston bombers Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Boston bombing suspect Dzhokhar Tsarnaev is detained by officers on Friday, April 19. After a car chase and shootout with police, one suspect in the Boston Marathon bombing, Tamerlan Tsarnaev, was shot and killed by police early Friday, and his brother and second suspect, Dzhokhar Tsarnaev, was taken into custody Friday night. The two men are suspects in the bombings at the Boston Marathon on April 15, that killed three people and wounded at least 170. See all photography related to the Boston bombings. Hide Caption 1 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Special imaging techniques employed by Massachusetts State Police reveal Boston Marathon bombing suspect Dzhokhar Tsarnaev hiding in a boat in a backyard in Watertown on April 19. Hide Caption 2 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Dzhokhar Tsarnaev gets out of the boat he was hiding in outside of a home in Watertown, as seen in a surveillance video still. Hide Caption 3 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – An ambulance carries Boston Marathon bombing suspect Dzhokhar Tsarnaev, 19, from the scene after he was apprehended in Watertown, Massachusetts, on April 19. Hide Caption 4 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police SWAT teams leave the area after apprehending the suspect in a yard where he was hiding in a dry-docked boat on April 19. Hide Caption 5 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Residents flee from an area where a suspect was hiding on Franklin Street on April 19. Hide Caption 6 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT team members run toward a police assault on a house as gunfire erupts on April 19. Hide Caption 7 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – People react while watching police respond to reported gunfire on April 19. Hide Caption 8 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT team members move down residential streets as they perform door-to-door searches in Watertown, Massachusetts, on April 19. Hide Caption 9 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A U.S. military helicopter lands behind Watertown Mall as law enforcement agencies continue to search for the 19-year-old bombing suspect on Friday. Hide Caption 10 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT teams prepare to enter a home as they continue the door-to-door search. Hide Caption 11 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – U.S. President Barack Obama meets with members of his national security team in the Situation Room of the White House on April 19 to discuss developments in the Boston bombings investigation. Hide Caption 12 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT team members line a residential street in Watertown, Massachusetts, as the manhunt continues on Friday. Hide Caption 13 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A man watches from the window of a home as a SWAT team member keeps watch on Friday, in Watertown, Massachusetts. Hide Caption 14 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police to continue to the door-to-door search on Francis Street in Watertown, Massachusetts, on Friday. Hide Caption 15 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Law enforcement officers place themselves in an overhead position on Arsenal Street as the search continues on April 19. Hide Caption 16 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Law enforcement officers react to what was initially thought to be a threatening suspect on Arsenal Street on April 19. Hide Caption 17 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A police SWAT team searches houses on April 19 for the second suspect. Hide Caption 18 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT teams searches homes along Winsor Avenue in Watertown on April 19. Hide Caption 19 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A Massachusetts state trooper watches other troopers line up at Watertown Mall as the manhunt for the second suspect continues in Watertown on Friday. Hide Caption 20 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police continue the ongoing manhunt for the second suspect on Williow Avenue in Watertown on Friday. Hide Caption 21 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A Watertown police vehicle with bullet holes in its body and a shattered windshield is towed out of the search area on April 19 in Watertown, Massachusetts. Hide Caption 22 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A Massachusetts State Police officer checks the bag of a cyclist amid heightened security on Friday in Watertown. Hide Caption 23 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Katia Costa looks out her window as police continue the manhunt on Nichols Avenue in Watertown on Friday. Hide Caption 24 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Ruslan Tsarni, uncle of the Boston terror suspects, told CNN affiliate WBZ that Tamerlan "got what he deserved" in an interview outside his home in Montgomery Village, Maryland, on Friday. Hide Caption 25 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A woman is questioned by Cambridge police and other law enforcement agencies Friday near the home of the second suspect in Cambridge, Massachusetts. A Massachusetts Institute of Technology campus police officer was shot and killed late Thursday night at the school's campus in Cambridge. A short time later, police reported exchanging gunfire with alleged carjackers in nearby Watertown. Hide Caption 26 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT teams move into position at the intersection of Nichols and Melendy avenues in Watertown, Massachusetts, on Friday. Hide Caption 27 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT teams gather at the intersection of Nichols and Melendy avenues in Watertown while searching for the remaining suspect on Friday. Hide Caption 28 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Onlookers take pictures while SWAT team members look around on Friday. Hide Caption 29 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Massachusetts Gov. Deval Patrick, left, speaks to the media at a shopping mall on the perimeter of a locked-down area during the search on Friday. Hide Caption 30 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Metro SWAT members hang off the back of a truck during the search on Friday. Hide Caption 31 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – SWAT officers check a door with guns ready on Friday. Hide Caption 32 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Officers patrol Watertown on Friday. Hide Caption 33 of 45 Photos: Photos: Manhunt for Boston bombers Photos: Manhunt for Boston bombers – The aftermath of the shootout that police said involved the two suspects in Watertown early Friday. Hide Caption 34 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police with guns drawn search for a suspect on Friday in Watertown, Massachusetts. Hide Caption 35 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A police officer runs with his gun drawn on Friday. Hide Caption 36 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Boston Police gather in the parking lot in front of a Best Buy store near the Watertown Mall on Friday. Hide Caption 37 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Boston Police Commissioner Edward Davis speaks during a media briefing in the parking lot of the Watertown Mall on Friday. Hide Caption 38 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Boston police gather in front of a Best Buy on Friday. Hide Caption 39 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police stop cars at School and Walnut streets on Friday. Hide Caption 40 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A Massachusetts state trooper checks a building along Mount Auburn Street as police search neighborhoods in Watertown. Hide Caption 41 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police search neighborhoods yard by yard on Friday. Hide Caption 42 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police convene on School and Walnut streets on Friday. Hide Caption 43 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – A police officer talks to a driver at a checkpoint in Watertown, Massachusetts. Hide Caption 44 of 45 Photos: Photos: Manhunt for Boston bombers Manhunt for Boston bombers – Police officers keep a man on the ground in Watertown on Friday. See all photography related to the Boston bombings. Hide Caption 45 of 45

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Law enforcement officials combed through photos and surveillance videos, searching for clues to who detonated the bombs. The FBI released photos showing two men they were seeking and asked for the public's help.

At the dorm where Tsarnaev lived, students joked Thursday as they viewed the FBI photos on television, a senior who lived in the suspect's dorm told The Boston Globe.

"We made a joke like, that could be Dzhokhar," said Pamala Rolon. "But then we thought it just couldn't be him. Dzhokhar? Never."

A tense scene began to unfold Thursday night -- complete with wailing sirens, flashes of blue and red lights, a hail of bullets and explosions from homemade bombs. By early Friday morning, Tsarnaev's older brother, Tamerlan, 26, was dead. Dzhokhar Tsarnaev was bleeding as he stole away into the night.

On campus nobody was joking. The school posted a message on its website: "UMass Dartmouth has learned that a person being sought in connection with the Boston Marathon bombing has been identified as a student registered at UMass Dartmouth. The campus is closed. Individuals on campus should shelter in place unless instructed otherwise."

The manhunt for Dzhokhar Tsarnaev lasted all day Friday and left Boston streets deserted as police asked everyone to stay indoors. Then after the request was lifted, authorities got a tip: A Watertown man told police someone was hiding in his boat in the backyard, bleeding. It was their suspect, Watertown police Chief Edward Deveau said.

Officers spotted Tsarnaev poking through the tarp covering the boat, and a shootout erupted, Deveau said. Police used "flash-bangs," devices meant to stun people with a loud noise, and negotiated with Tsarnaev for about half an hour.

"We used a robot to pull the tarp off the boat," David Procopio of the Massachusetts State Police said. "We were also watching him with a thermal imaging camera in our helicopter. He was weakened by blood loss -- injured last night, most likely."

A thermal image photograph, released Saturday by the state police, showed what authorities say was Tsarnaev lying in the middle of the boat.

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, Deveau said.

Eventually Tsarnaev stood up and lifted his shirt for the officers.

"Once we saw that, we felt comfortable enough to send some officer tactical equipment to grab him and pull him away from the boat," Deveau said. He was taken by ambulance to a hospital.

Police are confident there are no other suspects, Deveau said.

"These two acted together and alone," he said. "As far as this little cell and this little group, I think we got our guys."