Medical workers aid injured people at the finish line of the Boston Marathon after an explosion on April 15, 2013.

WASHINGTON — A divided Supreme Court seemed prepared Wednesday to allow the death sentence to be reimposed for Boston Marathon bomber Dzhokhar Tsarnaev after a federal appeals court voided it.

A majority of the justices suggested that they did not agree with defense claims that the trial judge improperly restricted the questioning of prospective jurors or was wrong to exclude evidence of a separate crime two years before the bombing.

Tsarnaev was convicted of joining his older brother, Tamerlan, in planting two pressure-cooker bombs near the marathon finish line in 2013 that killed three people and injured hundreds more, many of them seriously. In a separate phase of the trial, the jury recommended capital punishment for the deaths of the two people killed by the bomb that he placed.

But a three-judge panel of the U.S. Court of Appeals for the 1st Circuit last year ordered a new sentencing hearing. It ruled unanimously that the trial judge failed to allow enough questioning of potential jurors about how closely they followed the extensive news coverage of the bombings.

The appeals court also said the judge should have allowed Tsarnaev's lawyers to bring up a 2011 triple killing in the Boston suburb of Waltham that investigators suspected was committed by Tamerlan. The defense wanted to use it to show that the younger Tsarnaev was dominated by his violent older brother, and was therefore less responsible for the bombings because of Tamerlan's influence.

Tsarnaev's lawyers did not deny his role in the marathon bombing, but they said he was easily manipulated by his brother, a man they called the mastermind.

Although Attorney General Merrick Garland has ordered a moratorium on executions in the federal system, the Justice Department under President Joe Biden is nonetheless taking the same position that it did under the Trump administration, defending the death sentence for Tsarnaev.

During 90 minutes of courtroom argument Wednesday, few of the justices seem concerned about the judge's limit on questioning jurors. But some suggested they believe he was wrong to block evidence of the Waltham murder.

"The court let in evidence about Tamerlan assaulting people because it showed the kind of person he was, and yet it kept out evidence that he led a crime that resulted in three murders?" asked Justice Elena Kagan. "The court refused to allow evidence of a gruesome crime."

And Justice Stephen Breyer said that evidence was central to Tsarnaev's lawyers' arguments during the penalty phase. "This was their defense," he said. "They agreed he was guilty."

But Justice Department lawyer Eric Feigin said the evidence of who committed the Waltham murder was unreliable. Tamerlan and another man suspected to have been at the scene were both dead by the time of the trial. "The investigation had hit the end of the road. There was no way to know what happened," he said.

Chief Justice John Roberts seemed to agree. "It would focus the jury on something the judge concluded couldn't be resolved," he said.