9:35 A.M.

A medical examiner testifying in the trial of Boston Marathon bomber Dzhokhar Tsarnaev (joh-HAHR' tsahr-NEYE'-ehv) has described gaping leg wounds that caused a 23-year-old woman to bleed to death from one of the blasts.

Dr. Katherine Lindstrom says Lingzi Lu's femoral artery in her left leg was essentially cut in half, causing her to quickly bleed to death. Lu was a Chinese national and a graduate student at Boston University.

Lu was one of three people killed when twin bombs exploded near the marathon finish line on April 15, 2013. More than 260 others were injured.

During opening statements, Tsarnaev's lawyer admitted that he participated in the bombings but said his older brother, Tamerlan, was the mastermind. Tamerlan Tsarnaev died after a shootout with police days after the bombings.