Mr. Maher, walking in South Boston on the waterfront, lamented that Massachusetts seemed to be losing its lofty goals and a piece of its unique identity. “The Chinese put a lot of people to death, and we put a lot of people to death, and almost nobody else in the world does,” he said. “It’s kind of a brutal thing. And for this to happen in Massachusetts ...” His voice trailed off.

At the site of the bombing, Jessica Brown, an editor for a technology company, stared at the finish line while a companion from out of state took a photograph. The sentence had taken her, too, by surprise.

“I really thought they were going to do life in prison,” said Ms. Brown, who expressed some philosophical doubt about the death penalty.

“It raises the question of, should we react to murder with murder?” she said.

For her, the question hit close to home because she lives in Boston’s Dorchester neighborhood, near Bill and Denise Richard. The couple’s 8-year-old son, Martin, was killed by one of the bombs — but they nonetheless made an open plea to the government to drop its pursuit of the death penalty and send Mr. Tsarnaev to prison instead.

Some of the survivors of the bombings and their relatives felt very differently. Many supported the death penalty and expressed relief on Friday when word emanated from the courtroom that the jury had chosen it. Most were solemn, not triumphant.

“I feel justice for my family,” said Liz Norden, who went to court almost every day during the trial and whose sons, Paul and J. P., lost legs in the blasts. “I have to watch my two sons put a leg on every day, so, I mean, I don’t know — closure? But I can tell you, it feels like a weight has been lifted off my shoulders.”