Homicide

Witness says he saw Tsarnaev near slain MIT officer's police cruiser days after bombings

  • This undated forensics photograph released by the U.S. Attorney's office and presented as evidence during the federal death penalty trial of Dzhokhar Tsarnaev, Wednesday March 11, 2015, in Boston, shows a bloodied service pistol sitting on the seat of MIT Police Officer Sean Collier's cruiser. Tsarnaev is charged with conspiring with his brother to place two bombs near the Boston Marathon finish line that killed three and injured more than 260 spectators in April 2013. (AP Photo/U.S. Attorney's Office)

    This undated forensics photograph released by the U.S. Attorney's office and presented as evidence during the federal death penalty trial of Dzhokhar Tsarnaev, Wednesday March 11, 2015, in Boston, shows a bloodied service pistol sitting on the seat of MIT Police Officer Sean Collier's cruiser. Tsarnaev is charged with conspiring with his brother to place two bombs near the Boston Marathon finish line that killed three and injured more than 260 spectators in April 2013. (AP Photo/U.S. Attorney's Office)  (The Associated Press)

  • In this courtroom sketch, Dun Meng, far right, testifies with a translator at his side during the federal death penalty trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev in Boston, Thursday, March 12, 2015. Meng described his harrowing ride at gunpoint with the Boston Marathon bombers and the moment he made "the most difficult decision" of his life to bolt from the car. Tsarnaev is charged with conspiring with his brother to place two bombs near the marathon finish line in April 2013, killing three and injuring more than 260 people. (AP Photo/Jane Flavell Collins)

    In this courtroom sketch, Dun Meng, far right, testifies with a translator at his side during the federal death penalty trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev in Boston, Thursday, March 12, 2015. Meng described his harrowing ride at gunpoint with the Boston Marathon bombers and the moment he made "the most difficult decision" of his life to bolt from the car. Tsarnaev is charged with conspiring with his brother to place two bombs near the marathon finish line in April 2013, killing three and injuring more than 260 people. (AP Photo/Jane Flavell Collins)  (The Associated Press)

  • People leave federal court to board a bus carrying Boston Marathon bombing survivors, family and friends after attending the federal death penalty trial of Dzhokhar Tsarnaev in Boston, Thursday, March 12, 2015. Tsarnaev is charged with conspiring with his brother to place two bombs near the Boston Marathon finish line that killed three and injured more than 260 people in April 2013. (AP Photo/Elise Amendola)

    People leave federal court to board a bus carrying Boston Marathon bombing survivors, family and friends after attending the federal death penalty trial of Dzhokhar Tsarnaev in Boston, Thursday, March 12, 2015. Tsarnaev is charged with conspiring with his brother to place two bombs near the Boston Marathon finish line that killed three and injured more than 260 people in April 2013. (AP Photo/Elise Amendola)  (The Associated Press)

Jurors in the trial of Boston Marathon bomber Dzhokhar Tsarnaev heard a dramatic recording of a Massachusetts Institute of Technology police officer frantically calling for help after discovering an officer who'd been gunned down.

MIT Officer David Sacco Wednesday described receiving a call from a resident who heard loud noises and saw an MIT cruiser in a courtyard on the university's campus in Cambridge on April 18, 2013, three days after the bombings. He said he was unable to reach Officer Sean Collier and sent another officer to check on him.

The jury heard a recording of that officer yelling, "Officer down! Officer down!" when he discovered Collier shot multiple times and near death. "Get on it!" the officer yells.

Nathan Harman, 24, a student working toward a PhD in mathematics, said he was riding his bike through the courtyard at about 10:20 p.m. that day, when he saw a parked MIT police cruiser. Harman said the driver's-side door was open and there was a man bent at the waist and leaning in to the cruiser.

"He sort of snapped up, stood up and turned around, and he looked startled," Harman said. "And then I just didn't think anything of it and rode off."

When asked by a prosecutor if he saw the person in the courtroom, Harman pointed to Tsarnaev. "He's right there," he said.

Harman said he assumed Tsarnaev was an MIT student.

"I remember thinking he had a big nose, but nothing beyond that really," he said.

Prosecutors say Tsarnaev and his older brother, Tamerlan, killed Collier in a failed attempt to steal his gun. The shooting came hours after the FBI released images of the two brothers as suspects in the marathon bombing.

Tsarnaev's lawyers have admitted he participated in the bombing, but say Tamerlan was the mastermind. They also say it was Tamerlan who shot Collier while trying to steal his gun.

Three people were killed and more than 260 injured when the brothers set off two pressure-cooker bombs near the marathon finish line. Dzhokhar, now 21, faces the possibility of the death penalty if convicted.

Testimony was set to resume Thursday.