Lawyers for Boston Marathon bombing suspect Dzhokhar Tsarnaev asked a judge Wednesday to either get evidence from federal prosecutors of his older brother's alleged participation in a 2011 triple killing or postpone the trial, The Associated Press reports.
The lawyers say prosecutors haven't released any evidence of Tamerlan Tsarnaev's involvement in the murders since 2013 court papers. The older Tsarnaev was killed in a police shootout days after the 2013 bombing.
Assistant U.S. Attorney William Weinreb said federal prosecutors have no information to turn over.
William Fick, Tsarnaev's lawyer, called evidence relating to his client's brother "extremely relevant" because it could strengthen an argument that Dzhokhar Tsarnaev was coerced into carrying out the bombings by Tamerlan Tsarnaev.
Jury selection in Tsarnaev's trial is set to start Jan. 5.