BOSTON (REUTERS) - Attorneys representing accused Boston Marathon bomber Dzhokhar Tsarnaev on Monday asked the United States (US) District Court in Boston to add death-penalty specialist David Bruck to their team, part of an effort to spare the life of their 19-year-old client.
Tsarnaev, who is accused of killing four people and wounding more than 260 in the April 15 bombings and a later gun battle with police, faces the possibility of execution if convicted.
The ethnic Chechen and naturalised US citizen last week pleaded not guilty to all 30 counts in his first public appearance since his April 19 arrest.
His lawyers, who include top Boston public defender Miriam Conrad and death-penalty expert Judith Clarke, argued in a motion filed on Monday that the sheer scale of the case - in which authorities reviewed thousands of images taken at the crowded race finish and interviewed witnesses in the US and abroad - make the help necessary.
"Counsel expect that the amount of discovery that this investigation will produce will be truly massive," attorneys for the suspect wrote. "Even were this not a potentially capital case, the magnitude of the task confronting Mr. Tsarnaev's attorneys would be daunting."
Mr Bruck, who serves as a law professor and director of the Virginia Capital Case Clearinghouse at the Washington and Lee University School of law, has specialised in death penalty defences for more the three decades.
He has defence clients have included the men accused of hijacking a New York-bound PanAm flight from Karachi, Pakistan, in 1986 and the perpetrators of the 1998 bombing of the US embassy in Nairobi, Kenya.
Mr Bruck did not immediately respond to request for comment.
Tsarnaev and his 26-year-old brother, Tamerlan, are accused of placing a pair of homemade, pressure-cooker bombs at the race's finish line, where they ripped through a crowd of thousands of onlookers and athletes in the largest mass-casualty attack on US soil since 9/11.
Three people died in the bombing: 29-year-old restaurant manager Krystle Campbell, graduate student Lingzi Lu, 23; and 8-year-old Martin Richard. MIT police officer Sean Collier was killed three days later, according to the indictment.