U.S. Attorney Rachael Rollins said that, if instructed by Attorney General Merrick Garland, she would attempt to reinstate the death penalty against convicted Boston Marathon bomber Dzhokhar Tsarnaev.

The Supreme Court is weighing whether the 1st U.S. Circuit Court of Appeals in Boston in 2020 mistakenly threw out Tsarnaev’s death sentence for his role in  the bombing that killed three people near the finish line of the marathon in 2013. The appeals court ruled the trial judge improperly excluded evidence that could have shown Tsarnaev was deeply influenced by his older brother, Tamerlan, and was less responsible for the carnage. The appeals court also faulted the judge for not sufficiently questioning jurors about their exposure to extensive news coverage of the bombing.

In more than 90 minutes of arguments last October, the court’s six conservative justices seemed likely to rule the appeals court mistakenly threw out Tsarnaev’s death sentence, a decision that would reinstate his death penalty. Tsarnaev’s guilt in the deaths of the bombing victims is not at issue, only whether he should be sentenced to life in prison or to death.

If the justices affirm the lower court’s ruling, however, Tsarnaev would have to face a new sentencing trial, assuming the Biden administration decided to continue pressing for a death sentence. Justice Department lawyers urged the Supreme Court last year to “put this case back on track toward a just conclusion.”

“The jury carefully considered each of respondent’s crimes and determined that capital punishment was warranted for the horrors that he personally inflicted — setting down a shrapnel bomb in a crowd and detonating it, killing a child and a promising young student, and consigning several others ‘to a lifetime of unimaginable suffering,’“ they wrote.

President Joe Biden has called for an end to the federal death penalty, but his justice department has argued that the appeals court wrongly rejected Tsarnaev’s death sentence. Massachusetts has banned the death penalty. The state last executed someone in 1947. In 1984, the Massachusetts Supreme Judicial Court ruled that a death penalty law approved by voters was unconstitutional.