Dzhokhar Tsarnaev trial: Jurors hear graphic details of victim's injuries

A medical examiner testifying Thursday in the trial of Boston Marathon bomber Dzhokhar Tsarnev described in graphic detail the devastating injuries that ravaged the body of a 29-year-old woman and caused her to bleed to death on the pavement.

One juror cried and wiped her face with a tissue as the jury looked at autopsy photos and listened to the description of injuries suffered by Krystle Campbell. Judge George O'Toole Jr. would not allow the photos to be shown on public monitors; only the jurors saw them.

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Campbell, a restaurant manager, was one of three people killed when twin pressure-cooker bombs exploded near the finish line of the marathon on April 15, 2013. More than 260 people were injured, including at least 16 who lost legs.

Tsarnaev's lawyer admitted during opening statements at his federal death penalty trial that Tsarnaev participated in the bombings but said he fell under the influence of his late older brother, Tamerlan, whom the defence has portrayed as the mastermind of the attack.

Dr. Jennifer Hammers, the medical examiner who performed Campbell's autopsy, said she had wounds all over her body, including gaping wounds to her legs, third-degree burns to her back and numerous wounds from BBs and pieces of metal. She said she removed numerous pieces of flat metal and pellets embedded in Campbell's wounds.

"Many of them were very deep, through the whole surface of the skin into the muscle," Hammers said.

Campbell bled to death but not immediately, Hammers said.

"Based on those injuries, you would estimate that she could have lived for up to a minute?" Assistant U.S. Attorney William Weinreb asked.

"That's correct," Hammers responded.

On Monday, prosecutors plan to call two other medical examiners to testify about the deaths of eight-year-old Martin Richard, a Boston boy who was with his parents, sister and brother at the marathon, and 23-year-old Lingzu Lu, a graduate student at Boston University.

After that testimony, prosecutors are expected to rest their case in the first phase of the trial, the guilt phase. Then the defence will present its case, which is expected to be brief since Tsarnaev's lawyers have admitted his guilt.

During the second phase of the trial known as the penalty phase the same jury will decide if Tsarnaev is sentenced to death or spends the rest of his life in prison.

Tamerlan Tsarnaev, 26, died days after the attacks when he was wounded during a gunbattle with police and run over by Dzhokhar as he escaped. Dzhokhar was found more than 18 hours later, hiding in a boat parked in a yard in Watertown, Mass.

In other testimony Thursday, an FBI bomb expert said the pressure-cooker bombs used in the attack were not very difficult to build, using readily available parts and instructions easily found on the Internet.

Edward Knapp, a supervisory special agent with the FBI, identified photos of various bomb components found at the scene of the attacks, including hobby fuse, a toggle switch, small Christmas tree bulbs and electronic speed controllers from remote-controlled cars.