WATERTOWN — For 21 hours, this city just west of Cambridge sat at the center of the largest manhunt in recent state history. SWAT teams roamed the streets. Residents, fearing for their lives, holed up in their homes.
The two suspects in the Boston Marathon bombings wound up here, in a city unaccustomed to violence.
The siege of the roughly 20 blocks began when Dzhokhar Tsarnaev, 19, and his brother, Tamerlan Tsarnaev, 26, allegedly fleeing police after the shooting of an MIT police officer, led scores of officers on a a 6-mile chase, allegedly tossing homemade bombs at their pursuers.
When the saga ended, the community’s relief was evident: At the announcement that the second suspect had been captured, residents burst into applause, cheering as a long blue line of law enforcement officers left the city they had shut down.
“It will be a little easier to be in Watertown tomorrow,” said Dwayne Aljets, 59. “Much easier than it was today.”
Thursday night began quietly, but when police cornered the bombing suspects on Dexter Street, a firefight erupted and police vehicles came screeching to a halt at the corner of Arsenal and School streets.
“Everyone get the [expletive] back!” frantic officers screamed at residents caught in the chaos.
“How far back?” asked Adnis Karageorgos, a 39-year-old dental student who was startled by the sound of two explosions and found himself just blocks from the mayhem.
“It isn’t safe!” an officer yelled back to him before sprinting in the direction of the shooting. “Just go . . . run back . . . as far as you can get!”
And then, officers relayed the most stark warning:
“They’ve got bombs!” screamed federal officers, ripping handguns from their holsters as they hurried toward the shoot-out.
“Turn off your phones; they’ve got IEDs,” shouted another.
As a sea of officers converged, hundreds of Watertown residents instantly became captives of the drama on their doorsteps.
Beth Robinson and her husband, Paul, were startled awake by the popping gunshots shaking the night. They shrugged it off. But then came the explosions.
Terrified, the couple corraled their four children and raced to the basement, where they huddled on the steps.
Through her darkened basement window, Beth Robinson said, she saw people racing through her yard, and the bright flashing lights of police cruisers. It was terrifying.
“My daughter was scared. She was crying,’’ said Beth Robinson. “We just huddled there together, waiting for it to stop.”
When the shooting finally ended, State Police announced that more than 200 spent rounds, the remnants of homemade bombs and pipe bombs, and a pressure cooker had been found at the scene.
The Robinsons, who live on Dexter Avenue near Laurel Street, said officials discovered a piece of a pipe bomb in their front yard.
Though one suspect had been killed in the firefight, the second remained at large for much of the day. Police cordoned off a 20-block area, preventing residents from moving in or out. Each house had to be swept.
Katie Blouin, 24, said SWAT members entered her home on Mt. Auburn Streeet, ordering her boyfriend to lie on the ground while K-9 units searched the property.
The search complete, the officers left him with stern instructions: Keep the door locked and stay low to the ground.
Hundreds of reinforcements streamed into the police staging area at the Arsenal Mall over the next few hours, as the massive parking lot transformed into a makeshift military camp. With dawn breaking, the lot hummed with mammoth command vehicles, heavily armed SWAT teams, and National Guard Humvees.
Residents who slept through the commotion awoke to find heavily armed teams working their way down each street.
Engulfed in a seemingly never-ending wave of police cruisers, FBI agents, and yellow police tape, Watertown’s East End was kept locked tight for the day.
Watertown Square was desolate, the usually busy Starbucks and Dunkin’ Donuts both dark. Residents wandered warily in and out of their homes, curious, concerned, dazed, and also, as the day wore on, more than a little stir crazy.
“I’ve never seen anything like this before,” said Mark Sideris, Watertown’s Town Council president. He spent much of the day fielding the calls of residents trapped behind police barricades.
Sideris, who has led the city’s nine-member governing council since 2009, said that, without question, Friday will go down as the most frantic day in Watertown history, far surpassing the day in 2010 when two Times Square bombing suspects were captured in a Watertown home.
“This is 100 times more than that,” Sideris said.
As the manhunt stretched into the afternoon and early evening, city officials remained largely in the dark — relying almost exclusively on news reports for information — leaving them unable to effectively field the questions of residents desperately calling them for updates.
The perimeter began slowing expanding, as officers searched neighborhood after neighborhood for any sign of the escaped suspect.
While some feared the suspect had escaped Watertown, his final showdown with armed officials came in a Franklin Street backyard, just outside the original search area.
In the moments before, Marina Der Torossian’s 13-year-old daughter, tired of being confined indoors, decided to take a quick stroll. But as officers closed in on Franklin Street, she found herself cut off from her mother and 14-year-old brother Joey, who were evacuated to another street.
“I had no home to go to because they were blocking off the street, so I went and sat on someone’s steps,” said Julie Der Torossian. “I got scared, I didn’t know where he [suspect] was, and the shots sounded really close. I was panicking, shaking.”
As tactical officers closed in, some Franklin Street residents gathered on the top floors of their house, others in the dark, with their televisions turned on.
But the fright that had gripped the city turned to jubilation. As officers emerged from the yard declaring, “We got him,” residents broke into cheers.
“It’s overwhelming,” said Arman Dilan, who owns an apartment complex within the police perimeter and was holed up in his home much of the afternoon.
But even before the suspect’s capture, Dilan refused to allow the week’s events deter his spirit.
Around lunchtime, as convoys of police and emergency vehicles raced down the street, he hung a US flag in the complex’s doorway, offering a burst of patriotism in a city held hostage for a day.
Brian Ballou, Scott Helman, Meghan Irons, Akilah Johnson, Eric Moskowitz, Maria Sacchetti and Martine Powers, all of the Globe staff, and correspondents Christina Pazzanese and Andrew Tran contributed to this report. Wesley Lowery can be reached at firstname.lastname@example.org. Follow him on Twitter @WesleyLowery.