Lawyers in the prosecution and defense of Dzhokhar Tsarnaev sparred Wednesday over whether and when each side should disclose the strategy it will use when a jury considers whether the accused Boston Marathon bomber should be executed, if convicted.
Defense lawyers urged US District Court Judge George A. O’Toole Jr. to deny a request for disclosure of their mitigating arguments that was filed by US prosecutors, who are seeking the death penalty for a number of the charges against Tsarnaev.
“The government seeks an advance look at the defendant’s basic arguments for life, essentially his theory for why he should be allowed to live if convicted,’’ Tsarnaev’s defense team wrote in a filing in US District Court in Boston.
Prosecutors are not entitled to the list of mitigating factors until a jury has reached its verdict and only if that verdict calls for the imposition of the death penalty, the defense said.
Separately, prosecutors fired back at a move by Tsarnaev’s lawyers for a glimpse of the information the federal government is planning to use against the defendant so they can try to convince jurors that the death penalty should be applied.
“Because the government has provided notice of its intent to seek the death penalty and the theories on which it intends to proceed, the court should deny Tsarnaev’s request for the disclosure of additional information,’’ prosecutors wrote.
The office of US Attorney Carmen M. Ortiz said that the federal death penalty act “does not require the government to identify the evidence it will present in aggravation, let alone identify it over five months before trial.’’
Tsarnaev, 20, faces multiple charges that carry the possibility of the death penalty if convicted of setting off the April 15, 2013, bombs that killed three people and injured more than 260. He and his older brother and alleged accomplice, Tamerlan Tsarnaev, are also accused of shooting and killing an MIT police officer. Tamerlan Tsarnaev was killed during a confrontation in Watertown.
The decision on whether Dzhokhar Tsarnaev will be executed will be made by a jury during a second, sentencing phase, if he is convicted.
The defense said it had its own list of arguments against death “to focus the jury on some of the reasons why a client should be spared execution . . . but nothing about that practice requires or implies advance disclosure to the government.”
Defense lawyers said Ortiz’s office is asking for the information so it can prepare the questionnaire that prospective jurors will be required to fill out. Prosecutors, the defense said, do not need a peek into the defense strategy to decide how to approach the critical issue of jury selection.Milton J. Valencia of the Globe staff contributed to this report.