Russian relatives of Boston Marathon bomber Dzhokhar Tsarnaev (joh-HAHR' tsahr-NEYE'-ehv) are expected to testify at his trial as his lawyers continue to make their case to spare his life.

Five family members are expected to take the witness stand Monday in federal court.

Prosecutors urged Judge George O'Toole Jr. last week to press Tsarnaev's lawyers to make sure his relatives testify soon because 16 FBI agents have been assigned to guard and protect them while they are in the U.S. The relatives arrived in Boston on April 23.

Tsarnaev was convicted last month of 30 federal charges in the bombings, including 17 that carry the possibility of the death penalty.

Three people were killed and more than 260 were injured when two pressure-cooker bombs exploded near the finish line April 15, 2013.