Aloke Chakravarty

Aloke Chakravarty presented prosecution testimony and delivered the guilt-phase closing argument, contending that Dzhokhar Tsarnaev acted with independent intent as a partner in the attacks rather than merely following Tamerlan. On Day 43, he combined surveillance, communications, gun acquisition, extremist materials and physical evidence to request guilty findings on all 30 counts. He acknowledged that the evidence did not identify who shot Officer Collier. His proposed interpretation of a 19-second phone call as coordination was an inference, and he acknowledged that its words were unknown.

During jury selection, Chakravarty questioned prospective jurors about setting aside publicity-driven opinions and clarified their capital-punishment views. He challenged three defense peremptory strikes as discriminatory; the court accepted the defense's nonracial explanations. In evidentiary arguments, he distinguished motive evidence offered to prove intent from family and influence evidence offered as sentencing mitigation. No ruling was recorded in that exchange. He also sought immediate identification of proposed foreign witnesses for investigation and cross-examination preparation, while the judge reserved decision on the disclosure dispute.

His eyewitness examinations developed the Marathon setting, injuries and emergency response through authenticated photographs and accounts of efforts to help victims, including Lingzi Lu. Police and dispatch examinations traced the response to Collier's shooting, location of the carjacked Mercedes, the Watertown confrontation and the search ending at the boat. Chakravarty elicited Stephen Silva's account that he lent Tsarnaev a Ruger P95 and ammunition that were not returned, along with Silva's criminal history and cooperation incentives. On redirect, he explored the agreement's truthfulness requirements and the court's control over sentencing. Silva also corrected his earlier answer and acknowledged that an agent, not Silva, wrote an interview report.

Chakravarty's documentary examinations linked Twitter accounts to Tsarnaev, authenticated the surviving boat writing, and introduced computer files, messages, university records and Norfolk Street search evidence. Translation witnesses explained Russian file names and Chechen and Arabic terms while acknowledging contextual limits. Through Kevin Swindon, Chakravarty developed file verification and cross-device comparisons, but Swindon distinguished verification from extraction and qualified timestamps, completeness and user attribution. Through Matthew Levitt, he used paired displays to compare extremist publications with the boat writing. The court limited interpretation of a plain-English phrase; redirect distinguished radical ideas from violent action and confirmed that an Awlaki-related tweet predated the bombing by about a year.

His explosives examinations contrasted trace residue with intact materials and compared recovered bomb components with Inspire descriptions. Edward Knapp explained necessary activation steps and incompatible remote-control components without identifying who operated them. The court excluded David McCollam's undisclosed residue-proportionality opinion and reserved admission of the bomb mockups. Against defense digital analyses, Chakravarty tested whether phone plots, university swipes and browser records established movement or identified a component purchaser. Gerald Grant acknowledged important gaps but did not accept every proposed criticism of carrier data. Mark Spencer confirmed shared computer use and additional Sony searches, while maintaining that forensic artifacts could not identify the person at the keyboard or that person's thoughts. The court allowed publication of search entries but sustained several questions that asserted broader facts or exceeded scope.

In the penalty phase, Chakravarty elicited accounts of lasting injuries, prolonged treatment and Lingzi Lu's family grief. His mitigation cross-examinations tested witnesses' opportunities to know Tsarnaev and the reach of evidence about Tamerlan. Mosque witnesses qualified their accounts, including Tamerlan's persuasiveness and their contact with the defendant; Grant acknowledged having no evidence that Dzhokhar visited Tamerlan's YouTube site. Questions to teachers and friends exposed limits on knowledge of Tsarnaev's views and later life. Chakravarty challenged Elmirza Khozhugov's cultural claims, prior FBI statements and reliance on relatives for information. Khozhugov acknowledged greater familiarity with Tamerlan than Jahar, and the court sustained a question linking the defendant's bombing choice to April 15.