Nathan Harman , recounting his story publicly for the first time on Wednesday, told a federal jury that he was riding his bike through the MIT campus in Cambridge one night two years ago when he came upon a strange figure.
The man was leaning into a police cruiser. The driver's-side door was open, and the window down. "He sort of popped up, stood up, and turned around. He looked startled," said Harman, a 24-year-old graduate student.
The person was thin, and tall, but not as tall as Harman, who is six feet. He had a sweater with an emblem on the front, was wearing a hat, and something about his nose was remarkable.
In federal court in Boston Wednesday, a visibly nervous Harman saw that man again: Dzhokhar Tsarnaev, the surviving Boston Marathon bomber. Harman pointed and declared, "That's him, he has a blue shirt on."
Tsarnaev leaned forward, as if to make the identification easier.
Harman told his story as prosecutors focused on the night of April 18, 2013, when MIT police officer Sean Collier was fatally shot by Tsarnaev and his older brother, Tamerlan.
The brothers tried to take Collier's service weapon but failed, and fled the scene.
Harman did not see the shooting, but it appears he rode by moments after it happened. He said he thought nothing of his encounter at the time.
But several other witnesses who testified Wednesday recounted an emergency call reporting loud bangs on campus. Video surveillance taken from a nearby building shows two figures creeping toward Collier's cruiser, just as Harman was riding by. And police officers described how they arrived to find Collier tilting to the side, a wound in his temple, his neck, and on his right hand.
Video shows two people approaching MIT officer’s cruiser
Video surveillance taken from a nearby building shows two figures creeping toward MIT police officer Sean Collier cruiser on April 18, 2013, when Collier was fatally shot by Tsarnaev and his older brother, Tamerlan.
The 26-year-old MIT police officer had blood all over him, but he still had a pulse, and he was making a gurgling noise. Two officers pulled him out of the cruiser, though his foot was caught between the brake and the gas pedal.
"Just hang in there, you'll be OK," one of the officers told Collier, according to the account of MIT police Sergeant Clarence Henniger, the first to arrive at the scene.
The officer asked Collier who did this to him.
"I believe Sean at that time may have been unconscious," Henniger said.
Tsarnaev faces the possibility of the death penalty for his role in the April 15, 2013, Boston Marathon bombings, which killed three and injured hundreds, and for his involvement in the killing of Collier three days later. Three hours after Collier was killed, Tsarnaev and his older brother and accomplice, Tamerlan, engaged police in a shootout in Watertown. Tamerlan, 26, was killed.
Tsarnaev's lawyers have acknowledged that he committed the crimes. But they have sought to use the trial to show that his older brother was the mastermind, making their client less culpable and less deserving of the death penalty. Judy Clarke, one of Tsarnaev's lawyers, asserted in opening statements that Tamerlan was the one who shot Collier.
Prosecutors argue that the brothers were equal partners, using an FBI agent's testimony on Wednesday to show that they called each other in the minutes before and after they each detonated a bomb on Boylston Street. The bomb Tamerlan Tsarnaev left in front of Marathon Sports was the first to go off, and Dzhokhar Tsarnaev detonated the second explosive about 12 seconds later in front of Forum restaurant.
Collier was shot three days later, on Thursday, April 18. The FBI had released photos of the Tsarnaev brothers a few hours earlier at a 5 p.m. news conference identifying them as the suspects in the explosions. Tamerlan Tsarnaev called his younger brother later that night, at 11 p.m., according to the testimony of FBI agent Chad Fitzgerald.
Authorities have said the brothers planned to flee the area.
James Eppard, a public affairs manager for the FBI, told jurors Wednesday that the release of the photos of the suspects and surveillance footage attracted unprecedented attention: The video on the FBI's YouTube site was played 12 million times in the first 24 hours it was posted.
Police were first notified of Collier's shooting at 10:20 p.m.
A caller reported hearing possible gunshots outside the MIT Koch Institute, off Main Street, though he thought the sound was more like a drum.
"It sounds like somebody is hitting a trash can, it's really loud," the caller reported, according to a recording of the emergency call played for jurors. The caller could see a police cruiser outside, but no officer.
David Sacco, an MIT police officer who was working dispatch that night, said he tried to contact Collier, who was assigned to that area. They had been communicating earlier, by radio and by text message. But Collier did not respond to multiple attempts to reach him.
"It became an amount of time that wasn't comfortable," Sacco told the courtroom.
Henniger, the supervisory patrolman, found Collier in the driver's seat, slouching to the right. Blood was "all over the car, his body."
"All units respond, officer down, officer down," he screamed into his police radio. "Get on it."
Brandon O'Hearn, a Cambridge police officer, was responding to an armed robbery at a nearby 7-Eleven convenience store when he heard reports of an officer down, and responded to find the two MIT police officers tending to Collier.
"There was blood everywhere," O'Hearn testified. He said Collier was close to the cruiser, right by the driver's-side door, and he and another officer attempted to perform CPR until an ambulance arrived.
"It felt like a long period of time," he said. "His face and his neck were covered in blood, he had some type of wound to his neck, he was covered in blood."
Matthew Isgur, who runs the MIT video surveillance system, obtained video footage from a nearby building that — though the footage was taken from a distance away — shows two shadowy figures walk a distance along the Koch building, and creep up behind Collier's cruiser. There is a pause, and Collier's brake light flashes. A bicyclist, Harman, can be seen riding by. A brake light flashes again and stays on as the two figures race from the scene.
Henniger said Collier's gun belt and holster were covered in blood. It appeared that one of the holster's locking devices had been breached.
Prosecutors said blood-stained gloves were found in Tsarnaev's car that matched Collier's DNA.
MIT Police Chief John DiFava, a former State Police colonel, said the department had issued specialized, three-lock holsters for officers.
Removing an officer's handgun, if the officer was sitting in a police cruiser, "would be very difficult," he testified.
DiFava said he attempts to engage with his police officers when he sees them on the street, and he had seen Collier that night, just after 9:30, parked near a parking garage.
They spoke for roughly three minutes, DiFava said, and "I told him to be safe, and I left."
Dzhokhar Tsarnaev buys milk shortly after Marathon bombings
Dzhokhar Tsarnaev went to a Whole Foods grocery store in Cambridge, where surveillance video showed him pondering what type of milk to buy 23 minutes after the Boston Marathon bombing on April 15, 2013.