His two sisters were in court in Muslim garb. One was carrying a baby; the other wiped away tears with a tissue. Tsarnaev's parents remained back in Russia.
Tsarnaev's lawyer Judy Clarke, an expert in death penalty cases, asked that the judge enter not-guilty pleas for him, but U.S. Magistrate Judge Marianne Bowler said: "I would ask him to answer."
On the same day as the arraignment, Boston's police commissioner appeared on Capitol Hill and complained to a Senate panel that the Justice Department failed to share information on terrorism threats with local officials before the bombing.
"There is a gap with information sharing at a higher level while there are still opportunities to intervene in the planning of these terrorist events," Commissioner Edward F. Davis III said.
Reporters and spectators began lining up for seats in the courtroom at 7:30 a.m. as a dozen Federal Protective Service officers and bomb-sniffing dogs surrounded the courthouse. Four hours before the 3:30 p.m. hearing, the defendant arrived at the courthouse in a four-vehicle motorcade.
About a dozen Tsarnaev supporters cheered as the motorcade arrived. The demonstrators yelled, "Justice for Jahar!" as Tsarnaev is known. One woman held a sign that said, "Free Jahar."
Lacey Buckley said she traveled from her home in Wenatchee, Wash., to attend the arraignment. She said she believes he is innocent. "I just think so many of his rights were violated. They almost murdered an unarmed kid in a boat," she said.
A group of friends who were on the high school wrestling team with Tsarnaev at Cambridge Rindge and Latin waited in line for hours, hoping to get a seat.
One of them, Hank Alvarez, said Tsarnaev was calm, peaceful and apolitical in high school.
"Just knowing him, it's hard for me to face the fact that he did it," said Alvarez, 19, of Cambridge.
Prosecutors say Tsarnaev, a Muslim, wrote about his motivations for the bombing on the inside walls and beams of the boat. He scrawled that the U.S. government was "killing our innocent civilians," and also wrote: "We Muslims are one body, you hurt one you hurt us all."
Martin Richard, 8, Krystle Marie Campbell, 29, and Lingzi Lu, 23, were killed by the two bombs, which were fashioned out of pressure cookers, gunpowder, nails and other shrapnel. Numerous victims lost legs.