The capture of the Boston Marathon bombing suspect raises a host of freighted legal issues for a society still feeling the shadow of 9/11, including whether he should be read a Miranda warning, how he should be charged, where he might be tried and whether the bombings on Boylston Street last Monday were a crime or an act of war.

The suspect, Dzhokhar A. Tsarnaev, 19, was taken, bleeding, to a hospital on Friday night, and it remained unclear on Saturday whether he was conscious.

The authorities would typically arraign a suspect in a courtroom by Monday, a process that involves his being represented by a lawyer.

Most experts expected the case to be handled by the federal authorities, who were preparing a criminal complaint, including the use of weapons of mass destruction, which can carry the death penalty because deaths resulted from the blasts.

The decision to seek the death penalty must be made by Attorney General Eric H. Holder Jr. Under federal law, prosecutors must go through what is known within the Justice Department as a death-penalty protocol, under which the US attorney’s office and Justice Department lawyers in Washington analyse all aspects of the crime, as well as the defendant’s background, criminal history and other characteristics.”I think we can expect the prosecution to put together a meticulous case based on the forensic evidence, the videos, eyewitness test and any statements that the surviving defendant makes to the authorities,” said Kelly T. Currie, who led the Violent Crimes and Terrorism section in the Brooklyn US attorney’s office from 2006 to 2008, where he supervised a number of terrorism prosecutions.

“I would think it’s going to be a very strong case, and ultimately all the pieces put together are cumulatively going to show a pretty full mosaic of this defendant’s actions leading up to the attack and in its wake,” Currie said .Massachusetts has no death penalty, so a defence attorney in this case might seek to have the case tried in state court. State and county officials might also be eager to prosecute the defendant in the deaths of four of their residents.

President Barack Obama described the attack that Tsarnaev and his older brother, Tamerlan, 26, were accused of committing as “terrorism.” Tamerlan Tsarnaev was killed.

The administration has said it planned to begin questioning the younger Tsarnaev for a period without delivering the Miranda warning that he had a right to remain silent and to have a lawyer present.

Normally such a warning is necessary if prosecutors want to introduce statements made by a suspect in custody as evidence in court, but the administration said it was invoking an exception for questions about immediate threats to public safety. The Justice Department has pressed the view that in terrorism cases the length of time and type of questioning that fall under that exception is broader than what would be permissible in ordinary criminal cases, a view upheld by a federal judge in the case of the man convicted of trying to bomb a Detroit-bound airliner in 2009.

Civil libertarians have objected to the more aggressive interpretation of the exception to the Miranda rule, which protects the constitutional right against involuntary self-incrimination. Anthony D. Romero, the executive director of the American Civil Liberties Union, said that it would be acceptable to withhold Miranda before asking whether there were any more bombs hidden in Boston, but that once the FBI went into broader questioning, it must not “cut corners.”But some prosecutors suggested that if any confession was unnecessary to convict him, then the FBI might keep him talking without a warning without ultimately invoking the more disputed version of the public-safety exception to introduce it in court.

”I see a fairly strong case against this young man based on a great deal of evidence so, as a prosecutor, the top of my list would not be necessarily to Mirandize him and get a usable confession,” said David Raskin, a former federal prosecutor in terrorism cases in New York. At the same time, some Republican senators, including John McCain of Arizona and Lindsey Graham of South Carolina, argued that using the criminal-justice system was a mistake and that Tsarnaev should instead be held indefinitely by the military as an “enemy combatant,” under the laws of war, and questioned without any Miranda warning or legal representation, in order to gain intelligence.

Still, there is not yet any public evidence suggesting that Tsarnaev was part of Al Qaida or its associated forces — the specific enemy with which the United States is engaged in an armed conflict. And some legal specialists also doubted that the Constitution would permit holding a suspect like Tsarnaev as an enemy combatant. “This is an American citizen being tried for a crime that occurred domestically, and there is simply no way to treat him like an enemy combatant — not even close,” said Alan M. Dershowitz, a Harvard law professor and seasoned defence lawyer.

Whether legal proceedings take place in state or federal court - and both could occur, one after the other — a defence lawyer for Tsarnaev could contend that a fair trial was impossible in the Boston area and seek to have it moved. The lawyer could argue that so many people in Boston were affected by the bombings that no objective jury could be empanelled.

The trial of Timothy McVeigh, the Oklahoma City bomber responsible for killing scores and injuring hundreds in 1995, was moved to Colorado.On the other hand, witnesses and officials are all in the Boston area, and a trial that required them to travel extensively could be seen by a judge as an inappropriate burden on the community. Based on statements by the authorities to date, the case against Tsarnaev appears relatively strong. The FBI released videos showing him and his brother at the marathon in the area of the explosions, carrying backpacks like those that forensic tests indicated contained the pressure-cooker bombs that killed three and maimed scores. Boston’s top FBI official said when the videos were released that Tsarnaev, then identified as Suspect 2, placed one bag at the site of the second explosion, outside the Forum restaurant, moments before the second blast. Law-enforcement officials have also said the brothers admitted to the bombings — as well as to the killing on Thursday night of a Massachusetts Institute of Technology campus police officer — to a man whose car they stole at gunpoint. There is, in addition, the possibility of testimony by one of the bombing victims, a man whose legs were blown off, who told the FBI that he saw Tamerlan Tsarnaev place the other bomb. Officers who exchanged gunfire with the brothers Friday morning would also be witnesses, and their testimony would most likely focus on the gunbattle. Thomas Anthony Durkin, a defence lawyer and former assistant US attorney in Chicago, said he doubted that a fair trial could be had for Tsarnaev anywhere in the country, given the emotion around the case.

In any case, he said, the primary goal of a defence lawyer would be “to save his life.”

To that end, he and others said, three factors would most likely be highlighted — Tsarnaev’s relative youth, at 19; the influence his older brother seems to have had on him; and his own impressive past of sports, friendships and academic performance. Dershowitz, who said that any lawyer who took the case would become the most despised person in the country, agreed that a number of factors should play a role in preventing the death penalty. On the other hand, he noted, Tsarnaev is accused of putting down “a bag full of nails and bombs in front of an 8-year-old kid, and that will probably trump everything.”