Dzhokhar Tsarnaev’s boyish face inspired smitten fan clubs — even as surveillance images placed him at the Boston Marathon just before hell broke loose and his heat-signature showed him hiding in the boat where authorities say they found his scrawled Jihadi testament — but today, for the first time, the public has a chance to see the 19-year-old accused terrorist in person.

In what is expected to be an emotionally charged courtroom, Tsarnaev formally faces charges in a 3:30 p.m. arraignment in U.S. District Court alleging that he was behind the April 15 Boston Marathon finish line blasts that killed and maimed.

“People were killed, many others lost limbs. Dozens and dozens continue to suffer,” said former U.S. Attorney Michael Sullivan. “It’s an emotional day because of the horrific harm that he caused so many innocent people.”

Mayor Thomas M. Menino, who famously checked himself out of Brigham and Women’s Hospital to deal with the bombing aftermath, called the accused terrorist’s arraignment “another step in the healing process.”

“We have a good case against the guy,” Menino told the Herald. “We should lock him up and throw away the key.”

Tsarnaev faces 30 counts, including using a weapon of mass destruction and causing the deaths of four people — Martin Richard, 8, Krystle Campbell, 29, and Lingzi Lu, 23, were killed by bombs April 15, while MIT police officer Sean Collier, 26, was executed in his cruiser days later. Another 260 people were injured by the bombs.

All the marathon victims and their families have been invited to attend the hearing. The mother and uncle of the Norden brothers, who both lost legs, say they plan to be there for the men.

While the hearing could be limited to a pro forma reading of charges, experts say it is a venue where both defense attorneys and prosecutors might begin to make key legal moves and signal their strategies. No decision has been announced yet on whether the feds will seek the death penalty, but they may start to prepare the ground.

“I expect to hear an emphasis on the victimization, especially the deaths, because that’s what triggers death-penalty eligibility,” said Gerard T. Leone, the former federal attorney who successfully prosecuted Richard Reid, known as the shoe bomber. Reid said he expects lawyers gunning for Tsarnaev, 19, to allude to the death penalty; 17 of the charges he faces carry it.

He said if the death penalty is raised, the defense might ask for an expanded team to include an expert on the issue.

The defendant’s lawyers, meanwhile, could use the hearing to bring up problematic detainment issues.

Attorney Martin Weinberg, who is not part of Tsarnaev’s team, said defense lawyers may also start maneuvering to derail any death penalty bid. Tsarnaev’s team includes a top anti-death-penalty lawyer, Judy Clarke, who helped Tucson, Ariz., shooter Jared Loughner, Unabomber Ted Kaczynski, Atlanta bomber Eric Rudolph and child-killing mom Susan Smith all avoid the death penalty.

“You can’t start early enough,” Weinberg said, noting they are likely to focus on Tsarnaev’s youth and try to suggest he was not the key decision-maker in a plot with his slain brother, 26-year-old Tamerlan Tsarnaev.

But, Weinberg added, “It’s the first opportunity for a defendant to say ‘No’ to accusations of enormously serious charges. He’s still presumed innocent.”

Weinberg also said his lawyers should address conditions of Tsarnaev’s imprisonment.

“Month after month of solitary confinement can for some people have a diminished effect on the person’s concentration, their ability to focus,” Weinberg said. “If he doesn’t have appropriate access to lawyers and paralegals and investigators, this is the opportunity for a lawyer to begin to address those issues.”

Dave Wedge ?con­tributed ?to this report.