Dzhokhar Tsarnaev is the surviving offender in the attack on the Boston Marathon of April 15, 2013. Three people died near the finish line that afternoon: Krystle Campbell, 29, of Medford; Lingzi Lu, 23, from Shenyang in northern China; and a child aged eight. More than 260 others were injured. Three days later, on April 18, MIT Police Officer Sean Collier, 27, of Somerville, was killed, and federal prosecutors attributed his death to Tsarnaev and his older brother, Tamerlan. Tamerlan died in Watertown on April 19, 2013. Dzhokhar, then 19, was taken into custody in the same town that evening.
On April 8, 2015, a federal jury in Boston convicted him on all 30 counts of the indictment. On May 15, 2015, the same jury recommended death on six of the 17 capital counts, and on June 24, 2015, Judge George A. O'Toole Jr. formally imposed the sentence, together with consecutive life terms on the remaining counts. The death sentence has been through the federal appeals courts ever since. The First Circuit vacated it on July 31, 2020. The Supreme Court reversed that judgment on March 4, 2022, by a vote of 6 to 3. On March 21, 2024, the First Circuit sent the case back to the District Court to investigate claims that two jurors had been dishonest and possibly biased. When the last ruling in the case was issued, on July 31, 2025, that inquiry had not been decided. Tsarnaev is held in federal custody.
Dzhokhar Tsarnaev was born on July 22, 1993. His family came to the United States in about 2002, after time in Dagestan in Russia's North Caucasus, having come originally from Kyrgyzstan. He finished high school in Cambridge in 2011, where he was on the wrestling team, and that May he received a $2,500 city scholarship. Friends described him as smart and athletic.
He became a United States citizen on September 11, 2012.
Krystle Campbell was 29 and a native of Medford, Massachusetts. She never missed a Boston Marathon, and those who knew her described her as loud, fun and energetic. A school official called her a very energetic and likable woman with strong convictions.
Lingzi Lu was 23 and came from Shenyang, in northern China, and had been living in Boston.
The third person who died at the finish line was a child aged eight. The charge in his case, as in the others, was murder, with other charges.
Sean Collier was 27, a native of Wilmington, Massachusetts, who lived in Somerville. He joined the MIT Police on January 9, 2012, and the MIT police chief said he was born to be a police officer. Friends and colleagues described him as friendly, cheerful and kind. He liked hiking with friends, took up swing dancing and loved country music.
A fifth death is linked to the same week by the Boston Police Department, though it is not among the charged counts. Sergeant Dennis Simmonds of the Boston Police was among the first officers to respond in Watertown on April 19, 2013 and was injured there. He died on April 10, 2014, nearly a year later. In May 2015 the state retirement board recognized his death as one in the line of duty, relying on a state medical panel's finding that his injuries were consistent with the events in Watertown, but it did not count him as a victim of the attack on the marathon.
The attack at the finish line on April 15 killed three people and injured more than 260. On April 16, federal agents said they did not yet know who was responsible. On April 17, President Barack Obama signed an emergency declaration for Massachusetts and ordered federal aid to the state. The investigation was led by the FBI's Boston Division with the Boston Police Department and the Massachusetts State Police, and it drew in the Boston Joint Terrorism Task Force, whose more than 30 federal, state and local member agencies included ATF, Homeland Security Investigations, the U.S. Marshals Service, the Secret Service and the Massachusetts Bay Transit Authority, along with the Watertown, Cambridge and MIT police departments, the Boston Fire Department and the National Guard.
On April 18, investigators released photographs and video of two suspects and asked the public for help in identifying them. Later that day Officer Collier was killed. On April 19, authorities tracked the suspects to Watertown. Tamerlan Tsarnaev died there, and Dzhokhar Tsarnaev was located that evening and taken into custody. A shelter-in-place order that had covered much of the area was lifted. On April 22, 2013, he was formally charged in a federal complaint with offenses under 18 U.S.C. § 2332a.
On June 27, 2013, a federal grand jury returned a 30-count indictment against Tsarnaev, who was 19 and a U.S. citizen living in Cambridge. The counts included conspiracy and an offense resulting in death under 18 U.S.C. § 2332a; conspiracy and an offense resulting in death under § 2332f; conspiracy and malicious destruction of property resulting in death (§ 844(i) and (n)); two counts under § 924(c) and (j), one of them causing death; carjacking resulting in serious bodily injury (§ 2119(2)); and interference with commerce by threats or violence (§ 1951). Aiding and abetting was charged as well. Seventeen of the counts carried a maximum penalty of life in custody or death, and the rest carried a maximum of life or a fixed term of years.
The case was prosecuted by the U.S. Attorney's Office for the District of Massachusetts, led by U.S. Attorney Carmen Ortiz, with trial attorneys from the Justice Department's National Security Division and Criminal Division. The indictment named the conspiracy as running from February 13 to April 19, 2013, and treated Tamerlan Tsarnaev as a co-conspirator. Tsarnaev was arraigned on July 10, 2013, in a courtroom so crowded that an overflow room was opened. He entered a plea of not guilty to each count as it was read, and he was due back in court that September.
On January 30, 2014, Attorney General Eric Holder authorized prosecutors to seek the death penalty, and the government filed its notice of intent in the District Court. Holder said that he had weighed the facts, the applicable regulations and the submissions of the defense, and that the nature of the conduct and the resulting harm compelled the decision. Ortiz called it the product of careful and detailed consideration and said that rules limited what her office could say about the process.
Jury selection began in early January 2015. The District Court summoned 1,373 prospective jurors, and a 100-question form reduced that pool to 256. Individual questioning then ran for about three weeks and produced the twelve seated jurors. The judge had refused to include one proposed question that would have asked each prospective juror to list everything they had learned about the case from the media, calling it unfocused. That ruling, and the broader question of whether a trial could be held fairly in Boston, became central to the later appeals. During selection, a third of the jurors said they had already formed an opinion on guilt, and the defense's requests to move the trial out of Boston were denied.
Opening statements came on March 4, 2015, more than a month later than planned. The prosecution, led by Assistant U.S. Attorney William Weinreb, described the human toll of April 15 and of the days that followed, and it tied Tsarnaev to the events in Watertown. The defense, led by Judy Clarke, did not dispute that he had taken part. Its case was that he had acted under the influence of his older brother, and its purpose was to persuade the jury to spare him a death sentence. Before the opening statements Judge O'Toole had granted a prosecution motion to exclude some evidence the defense wished to offer in mitigation, while acknowledging that some evidence about the brother would be unavoidable.
The jury heard closing arguments on Monday, April 6, and began deliberating on Tuesday, April 7. After about 12 hours, a little longer than expected, it returned its verdict on April 8: guilty on all 30 counts. The judge told jurors that aiding and abetting was a single concept, so that Tsarnaev could be convicted for crimes committed directly by his brother as well as for his own. The case then moved to a sentencing phase before the same jury, which had to choose between death and life in custody. A death sentence required the agreement of all twelve.
In the penalty phase, survivors and family members of those who died testified for the prosecution. Prosecutors presented Tsarnaev as an equal partner in the crimes. The defense argued that he had been led by his older brother, and it called teachers, friends and relatives from Russia, who described him as a kind boy. A member of the clergy was the last defense witness and said that he had expressed sorrow for the victims. Tsarnaev did not testify.
On May 15, 2015, after about 14 hours of deliberation over three days, the jury recommended death. It completed a 24-page verdict form that took nearly half an hour to read aloud. It agreed with the prosecution on 11 of 12 aggravating factors, which included the killing of a child, and only three of the twelve jurors found that he had acted under his brother's influence. Of the 17 capital counts, the jury recommended death on six, all of them relating to the deaths of Lingzi Lu and the child. It did not recommend death on the counts relating to Officer Collier. By law the judge had to follow the recommendation. Ortiz said that Tsarnaev would pay for his crimes with his life.
Judge O'Toole imposed the sentence on June 24, 2015. About two dozen victims and relatives gave impact statements. Tsarnaev rose and, for the first time since his arrest, apologized to the victims and survivors in an address of about five minutes. He said he was sorry for the lives he had taken and wished the victims comfort and recovery. The sentence was death on the counts tied to the deaths at the finish line and multiple consecutive life sentences on the other counts. The First Circuit later counted the life terms at 20.
The appeal was decided on July 31, 2020, by a panel of Judges Torruella, Thompson and Kayatta, with Judge Thompson writing. The court held that the trial judge had erred by not asking prospective jurors what specifically they had seen, read or heard about the case, in light of the extensive publicity. It applied its own earlier rule, the Patriarca decision, which requires such questions when pretrial publicity is heavy, and concluded that in a capital case the error required vacating the death sentences. It also held that the trial judge had abused his discretion in excluding evidence at the penalty phase of the brother's alleged role in a 2011 killing in Waltham, which the defense said showed the brother's influence over Tsarnaev. The court found that evidence reliable enough for a jury to weigh and said the judge could have used limiting measures instead of excluding it altogether.
The court also reversed three convictions under 18 U.S.C. § 924(c), Counts 13, 15 and 18, and directed that judgments of acquittal be entered on them, because the underlying offenses were not all crimes of violence. It affirmed the other convictions and the life sentences, which Tsarnaev had not challenged on appeal. It vacated the death sentences on Counts 4, 5, 9, 10 and 14 and ordered a new penalty phase before a new jury. Judge Torruella agreed with most of the opinion but wrote separately that the pretrial publicity required a presumption of prejudice and a change of venue. The court noted that Tsarnaev would remain in custody for the rest of his life whatever happened and that the only open question was whether he would be executed.
The Justice Department petitioned for review, and the Supreme Court heard argument on October 13, 2021. It decided the case on March 4, 2022, by 6 to 3, with Justice Thomas writing for the majority, joined by Chief Justice Roberts and Justices Alito, Gorsuch, Kavanaugh and Barrett. The Court reversed the First Circuit's judgment. On jury selection, it held that the Sixth Amendment does not require judges to ask prospective jurors what they have learned from the media, that trial judges have broad discretion over voir dire, that the questionnaire and extended questioning in this case were reasonable, and that a court of appeals cannot use its supervisory power to impose a rule that overrides that discretion. Justice Barrett, joined by Justice Gorsuch, concurred and questioned whether courts of appeals have such supervisory power at all.
On the excluded evidence, the majority held that the Federal Death Penalty Act, at 18 U.S.C. § 3593(c), lets a judge exclude information whose value is outweighed by the danger of confusing or misleading the jury, and that the trial judge's conclusion that the evidence about the brother was not sufficiently established was not an abuse of discretion. Justice Breyer dissented, joined by Justice Kagan and, for most of the opinion, Justice Sotomayor. The dissent would have admitted the evidence as relevant and reliable and would have ordered a new sentencing proceeding. The ruling was limited to the two issues the First Circuit had decided, so the First Circuit's other holdings stood and several questions were left open for it to decide.
On remand from the Supreme Court, the First Circuit decided the issues that remained. Its opinion of March 21, 2024, written by Judge Kayatta, found no abuse of discretion in the denial of a change of venue from Boston. It upheld the excusal of one prospective juror whose views on the death penalty would substantially impair his service. It found, however, that the trial judge had not adequately investigated plausible claims that two seated jurors, identified as Jurors 138 and 286, had been dishonest during questioning and might have been biased.
The defense said that one of them, a woman, had told the court that she had not commented about the case online but had reposted a message insulting Tsarnaev, and that the other, a man, had said none of his Facebook friends had commented on the trial although one had urged him to play the part in order to be seated. Defense lawyers said both jurors had been untruthful and had raised the concern at the time. A Justice Department lawyer acknowledged that the jurors had made inaccurate statements but argued that they had misremembered and had not lied, and that the judge had done nothing wrong. The court said there could be innocent explanations, such as forgotten posts or misunderstood questions, but that the judge had to rule out the more troubling ones.
The panel voted 2 to 1, with Judges Kayatta and Thompson in the majority and Judge Howard dissenting. It remanded to Judge O'Toole to determine why each of the two jurors gave the answers at issue and whether either should have been struck for cause. If either should have been, the death sentence must be vacated and a new penalty phase held; if neither should have been, the sentence stands. The court said that a defendant generally carries the burden of proving juror bias by a preponderance of the evidence, but that if fading memories after the long delay prevent the judge from resolving the question, a new penalty phase will be required. The opinion again noted that the life sentences would continue in either case.
In August 2024 Tsarnaev's lawyers asked the First Circuit to remove Judge O'Toole from the remand, citing comments he had made about the case on podcasts and at public events during the appeals. On July 31, 2025, the First Circuit denied the request in a two-page judgment. It held that two panel discussions and a podcast about managing complex jury trials and the challenges social media poses for them did not warrant removal, and that the defense had not shown irreparable harm from keeping the judge on the case. Judge O'Toole therefore continues to preside over the inquiry into Jurors 138 and 286.
When the First Circuit ruled on July 31, 2025, no decision on the juror question had been issued, and it was unclear when the judge would rule. Tsarnaev's guilt is not in dispute in these proceedings. He is held in federal custody. When the outgoing President, Joe Biden, commuted the sentences of 37 of the 40 people then on federal death row on December 23, 2024, Tsarnaev was one of the three whose sentences were left in place, with Dylann Roof and Robert Bowers.
Tsarnaev was prosecuted in a federal court, so the sentence he received comes from federal law. In such a case the Attorney General must authorize prosecutors to seek death and the government files a notice of intent with the court, as happened in January 2014. The trial then has two parts, a guilt phase and a sentencing phase, before the same jury. For a death sentence the jury must be unanimous, and if it is not, the defendant receives life in custody. When the jury does recommend death, the law requires the judge to impose it. The sentencing phase is governed by the Federal Death Penalty Act, which allows judges to admit information at that stage but also to exclude it when its value is outweighed by the risk of confusion.
The practice of executions under federal law has varied sharply during the years of this case. The Trump administration resumed federal executions in July 2020 after a pause of 17 years and carried out 13 in six months. The Biden administration had asked the Supreme Court to take up Tsarnaev's case, and the Court heard argument in it in October 2021.
Several questions in the case were contested at the time and remain so in part. The first is the role of Tamerlan Tsarnaev. The defense maintained at both phases that the older brother led and that Dzhokhar followed, and three of the twelve jurors accepted that this had influenced him; the prosecution described the younger brother as an equal partner, and the jury agreed with the prosecution on the aggravating factors. The First Circuit would have allowed the jury to hear more about the brother's alleged part in a 2011 killing in Waltham, and the Supreme Court held that the trial judge was entitled to exclude it.
The second is the juror inquiry. Whether Juror 138 or Juror 286 gave untruthful or merely mistaken answers has not been decided, and the judge's findings, when they come, will determine whether the death sentence is vacated.
1993: Dzhokhar Tsarnaev is born; the family reaches the United States in about 2002.
September 11, 2012: He becomes a United States citizen.
April 15, 2013: Three people die at the Boston Marathon finish line; more than 260 are injured.
April 18, 2013: Investigators release photographs and video of two suspects; MIT Police Officer Sean Collier is killed.
April 19, 2013: Tamerlan Tsarnaev dies in Watertown; Dzhokhar Tsarnaev is taken into custody there that evening.
April 22, 2013: He is charged in a federal complaint.
June 27, 2013: A federal grand jury returns a 30-count indictment.
July 10, 2013: He pleads not guilty to all counts.
January 30, 2014: Attorney General Holder authorizes seeking the death penalty; the notice of intent is filed.
April 10, 2014: Boston Police Sergeant Dennis Simmonds dies.
January 2015: Jury selection begins; 1,373 prospective jurors are summoned.
March 4, 2015: Opening statements.
April 8, 2015: Guilty on all 30 counts.
May 15, 2015: The jury recommends death on six counts.
May 2015: The state retirement board recognizes Sergeant Simmonds's death as in the line of duty.
June 24, 2015: Judge O'Toole formally imposes the death sentence and consecutive life sentences.
July 31, 2020: The First Circuit vacates the death sentences and reverses three § 924(c) convictions.
October 13, 2021: The Supreme Court hears argument.
March 4, 2022: The Supreme Court reverses the First Circuit's judgment, 6 to 3.
March 21, 2024: The First Circuit, 2 to 1, remands for an inquiry into Jurors 138 and 286.
August 2024: The defense moves to remove Judge O'Toole.
December 23, 2024: President Biden commutes 37 federal death sentences; Tsarnaev's is not among them.
July 31, 2025: The First Circuit denies the request to remove Judge O'Toole; the juror inquiry remains open.