Accused Boston Marathon bomber Dzhokhar Tsarnaev professed his innocence today in federal court, making a quick but dramatic first appearance under the stares of victims and their family members as he recited "not guilty" seven times in a thick accent.

Judge Marianne Bowler's courtroom was packed for the 19-year-old's arraignment on 30 charges, including use of a weapon of mass destruction resulting in death.

Two women believed to be his sisters, one carrying a baby, cried in court as Tsarnaev appeared shackled and handcuffed while dressed in an orange prison jumpsuit.

The courtroom, packed with many turned away to a spillover room, was silent as the accused teen killer was arraigned.

Marathon bombing victims and their families, spectators and media began lining up for a look at the alleged bomber as early as 7:30 a.m. for the 3:30 p.m. hearing. Some even clashed with Tsarnaev's sympathizers.

"I have sympathy for the victims. I can see where they are coming from," said Tsarnaev supporter Jennifer Mack of Boston. "At the same time, this is my country. I can support who I want."

Seventeen of the charges qualify for the death penalty; U.S. Attorney General Eric Holder will decide whether to pursue Tsarnaev's execution if he is convicted.

Authorities say Tsarnaev, 19, and his brother Tamerlan, laid the crude pressure-cooker bombs killing three — Martin Richard, 8; Krystle Marie Campbell, 29; and Lingzi Lu, 23 — and wounded 280 in the April 15 terrorist attack at the Marathon finish line on Boylston Street. They are also accused of ambushing and fatally shooting MIT campus cop Sean Collier in a desperate bid to flee after the FBI released their photos to the public three days after the explosions.

The elder Tsarnaev was killed after his brother, fleeing from a firefight that night with cops in Watertown, ran him over in a car. Cops captured Dzhokhar hiding in a drydocked boat a short distance away after an intense daylong manhunt.

Police also lined up outside federal court in Boston today in a show of support for officer Collier.

Security at the federal court on Boston's waterfront was extraordinarily tight. The probable cause hearing was held next door to the ongoing mass murder trial of former FBI Most Wanted fugitive James "Whitey" Bulger.

Supporters, including one who came all the way from Washington state, said they believe Tsarnaev is innocent.

"I see zero evidence to say he actually did this," added Lacey Buckley, 23, of Washington state. "There is no DNA; there are no fingerprints. They got nothing."

About a half dozen supporters, all young women, wore T-shirts that read "Free the Lion" and "Dzhokhar is innocent."

Another woman in court told the Herald the T-shirts "made her sick."

MIT police Chief John DiFava said he wanted to be in court for his slain officer. "I wanted to get a look at him … He's a punk," said DiFava, adding he wants the death penalty if Tsarnaev is found guilty.

Lawyers said 80 to 100 witnesses will be called in the trial that could last about four months.

Dzhokhar was taken away in a white prison van right after the hearing.

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