Boston Marathon bomber's life could hang in balance

Convicted Boston Marathon bomber Dzhokhar Tsarnaev returns to court for the sentencing phase of his trial Tuesday.

The guilt phase's outcome was all but certain, with even defense lawyers flat out admitting their client took part in the bombing. But this next chapter is far less predictable, especially with an ongoing debate in Boston over whether Tsarnaev should live or die, reports CBS News correspondent Don Dahler.

In their fight to save Tsarnaev's life, the defense is expected to paint him as a troubled teenager under the influence of his radicalized older brother, Tamerlan.

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The team will likely put Tsarnaev's family members and friends on the stand.

But prosecutors are expected to remind the court of the brutality the 21-year-old helped mastermind two years ago, leading to the deaths of four people, including 8-year-old Martin Richard.

The younger Tsarnaev can be seen in surveillance video setting his bomb down just feet away from the child.

There is strong opposition to capital punishment in Massachusetts, which abolished its state death penalty in 1984. Many wonder if a jury in the state could hand down the death penalty.

"I'm not a big advocate of the death penalty. I've never been extremely supportive of it. I think it has its place and I think this is a place," former Boston police commissioner Ed Davis said.

He was commissioner at the time of the bombings.

Still, a recent poll showed a majority of Bostonians are against Tsarnaev paying with his life.

In a Boston Globe essay, Martin Richard's family urged prosecutors to take the death penalty off the table, saying, "We know that the government has its reasons for seeking the death penalty, but the continued pursuit of that punishment could bring years of appeals and prolong reliving the most painful day of our lives."

Jessica Kensky and Patrick Downes, who each lost limbs in the attack, joined the Richards' plea Sunday, saying, "We must overcome the impulse for vengeance."

"There are certainly times where we feel angry or we have frustration and we have vengeance on our minds, but I don't feel like that's a great use of our energy," Downes said.

Prosecutors need a unanimous vote for the death penalty, meaning if even one juror goes against it, Tsarnaev will get life in prison. The sentencing phase could last three to four weeks.