Edward Davis says he would have no sympathy for Dzhokhar Tsarnaev if, as expected, prosecutors push for death sentence

The Boston police commissioner who led the hunt for the Boston marathon bombers has said that he is comfortable with the surviving suspect facing the death penalty.

Edward Davis said he had no sympathy for Dzhokhar Tsarnaev, and when asked how he felt about the possibility that he could be sentenced to death, Davis replied: "That's fine with me."

The US government is likely to take at least a year to decide whether or not to seek the death penalty forTsarnaev, according to legal experts.

Tsarnaev, 19, is likely to have to wait until the summer of 2014 before he learns whether he might face lethal injection for his alleged role in the bombings that killed three people and injured more than 250. The calculation will ultimately be made by Eric Holder, the US attorney general, acting on the advice of prosecutors in Massachusetts, led by US attorney Carmen Ortiz, as well as a special review panel in Washington DC.

Speaking on the BBC's Today programme on Saturday, Davis said that the Tsarnaev brothers appeared to have directed their social frustrations to political extremism rather than common crime.

"The way this is shaping up is that we have disaffected young men in inner city neighbourhoods who are involved in violence all the time and we normally deal with this in gang activity. In this case the motive is not drugs or gangs, it's extremism, he said.

"Its important that society does as much outreach to people who are marginalised as possible."

But he said such concerns should not be mistaken for sympathy. "I watched this young man put a satchel on the ground which blew up and killed an 8-year old boy and a young woman standing next to him. I have no sympathy for him."

The question of whether or not to try the alleged marathon bomber as a capital case is one of the resounding challenges facing prosecutors, which they will begin deliberating once formal charges have been brought before a grand jury. Given the horrific nature of the Boston bombing and the large number of victims, there is already mounting political pressure to go for capital punishment, with two prominent Democratic senators, Charles Schumer and Dianne Feinstein, having indicated they favour it.

Pushing prosecutors in the other direction is the fact that Massachusetts, the state in which the bombings took place, does not have the death penalty on its statute books. Prosecutors will have to take on board the possibility that a local jury might be disinclined to impose a death sentence given the prevailing opposition to it within the state.

At several stages in the review process, Tsarnaev's defence lawyers will also be allowed to present their arguments for why he should be spared the death chamber. They are likely to ask for time to be able to assemble evidence relating to his background, influences and other mitigating factors, which may last several months.

Sam Buell, a law professor at Duke University and a former federal prosecutor in Boston, said that "based on what we now know, it seems likely that the government will seek the death penalty". But he added that the outcome would not be certain until the defence had presented its case.

Federal prosecutors have been known to drop the death sentence as part of a plea bargain in which the defendant pleads guilty or agrees to testify against others. But Buell thought that a plea bargain was unlikely, at least early on in the Tsarnaev prosecution, as it might appear to be insensitive towards the victims of the bombing.

Even if prosecutors seek the death penalty for Tsarnaev, they might not manage to persuade the jury to return a death sentence. Zacarias Moussaoui, who was charged with capital crimes in connection with 9/11, escaped execution when a federal jury in Virginia rejected the death penalty for him in 2006.

Should Tsarnaev be found guilty and put on federal death row, that too would be just the start of it. Like any death row, the federal one is beset with legal issues that tend to delay the actual carrying out of the ultimate punishment for years, if at all.

Only three people have been executed since the federal death penalty was restarted, in 1988. The most famous of those was Timothy McVeigh, the Oklahoma City bomber, who in effect volunteered to die by suspending his appeals and was executed in 2001.

In Tsarnaev's case there would be an added problem: he would not be able to be executed in Massachusetts as it has prohibited the practice, so would have to be sent to a neighbouring state that does allow capital punishment.

© Guardian News and Media 2013