The Obama administration said it had no choice but to prosecute Tsarnaev in the federal court system. Some politicians had suggested he be tried as an enemy combatant in front of a military tribunal, where defendants are denied some of the usual U.S. constitutional protections.
But Tsarnaev is a naturalized U.S. citizen, and under U.S. law, American citizens cannot be tried by military tribunals, White House spokesman Jay Carney said. Carney said that since 9/11, the federal court system has been used to convict and imprison hundreds of terrorists.
In its criminal complaint, the FBI said it searched Tsarnaev's dorm room at the University of Massachusetts-Dartmouth on Sunday and found BBs as well as a white hat and dark jacket that look like those worn by one of one of the suspected bombers in the surveillance photos the FBI released a few days after the attack.
Seven days after the bombings, meanwhile, Boston was bustling Monday, with runners hitting the pavement, children walking to school and enough cars clogging the streets to make the morning commute feel almost back to normal.
Residents paused in the afternoon to observe a moment of silence at 2:50 p.m., the time of the first blast. Church bells tolled across the city and state in tribute to the victims.
Standing on the steps of the state Capitol, Massachusetts Gov. Deval Patrick bowed his head and said after the moment of silence: "God bless the people of Massachusetts. Boston Strong."
On Boylston Street, where the bombing took place, the silence was broken when a Boston police officer pumped his fists in the air and the crowd erupted in applause. The crowd then quietly sang "God Bless America."
Also, hundreds of family and friends packed a church in Medford for the funeral of bombing victim Krystle Campbell, a 29-year-old restaurant worker. A memorial service was scheduled for Monday night at Boston University for 23-year-old Lu Lingzi, a graduate student from China.
Fifty-one victims remained hospitalized Monday, three of them in critical condition.
At the Snowden International School on Newbury Street, a high school set just a block from the bombing site, jittery parents dropped off children as teachers -- some of whom had run in the race -- greeted each other with hugs.
Carlotta Martin of Boston said that leaving her kids at school has been the hardest part of getting back to normal.
"We're right in the middle of things," Martin said outside the school as her children, 17-year-old twins and a 15-year-old, walked in, glancing at the police barricades a few yards from the school's front door.
"I'm nervous. Hopefully, this stuff is over," she continued. "I told my daughter to text me so I know everything's OK."
Tsarnaev was captured Friday night after an intense all-day manhunt that brought the Boston area to a near-standstill. He was cornered and seized, wounded and bloody, after he was discovered hiding in a tarp-covered boat in a Watertown backyard.
He had apparent gunshot wounds to the head, neck, legs and hand, the FBI said in court papers.
Meanwhile, investigators in the Boston suburb of Waltham are looking into whether there are links between Tamerlan Tsarnaev and an unsolved 2011 slaying. Tsarnaev was a friend of one of three men found dead in an apartment with their necks slit and their bodies reportedly covered with marijuana.