Harrowing victim testimony as Boston bomber impervious

The brother and step-father of the policeman shot dead by the Boston bombers gave harrowing, tear-jerking testimony Wednesday as convicted killer Dzhokhar Tsarnaev sat emotionless in court.

The 21-year-old former university student will be sentenced either to death or to life in prison without parole by a jury after the second phase of his trial, now underway in the northeastern US city.

Sean Collier, 27, was campus police officer at the Massachusetts Institute of Technology, one of the most prestigious universities in the country, when the Tsarnaev brothers shot him dead on the night of April 18, 2013.

"It's been a terrible two years," step father Joseph Rogers, 58, told court. He married Collier's mother more than 20 years ago, and the blended family grew up together, six children in all.

One woman on the jury cried as Rogers told of the phone call announcing that Sean had been shot and the rush to the hospital.

"All the children showed up," he said. Rogers and his wife saw Sean's bloodied body in a hospital room. "He had a hole in the middle of the head, he was shot to pieces."

Tsarnaev, dressed in a brown blazer and white shirt, refused to look at Rogers, maintaining the impervious expression that he has adopted since his federal trial began in early March.

"There is somebody missing. Thanksgiving and Christmas will never be the same," said Rogers.

"It is still a huge loss for me and my family for the rest of our lives," Sean's younger brother Andrew Collier told the court.

"I miss everything about him," he said, telling of the generosity of spirit and sense of duty of a brother who jad wanted to be a policeman for as long as he could remember.

- Video from cell -

Tsarnaev was convicted on April 8 on all 30 counts related to the April 15, 2013 Boston Marathon bombings, Collier's murder, a carjacking and a shootout while he was on the run.

Of part Chechen descent, Tsarnaev moved to America with his family aged eight took US nationality a year before carrying out the bombings, which killed three and wounded 264 more.

Prosecutors have described him as "America's worst nightmare" and argue he deserves to die for perpetrating one of the bloodiest attacks on US soil since 9/11.

They have released a screen grab of Tsarnaev, dressed in an orange prison jumpsuit flipping his middle finger at a surveillance camera in a cell before his first arraignment.

"This is Dzhokhar Tsarnaev, unconcerned, unrepentant and unchanged," said Assistant US Attorney Nadine Pellegrini on Tuesday.

The defense went on the counter-attack Wednesday, admitting into evidence a video clip that showed Tsarnaev pacing in his cell, approaching the camera, appearing to fix his hair and flashing his finger for a second.

He waited in the cell that day four hours, said Marshal Gary Oliveria on the witness stand.

Under cross-examination from defense lawyer Miriam Conrad he admitted writing a report on the finger flashing three days later at the request of superiors.

Tsarnaev watched the video without noticeable reaction.

- Thoughts of death -

Among the other witnesses called by prosecutors, was Adrianne Haslet-Davis, 34, a ballroom dancer who was amputated below the knee after she was wounded in the bombing.

At times breaking down uncontrollably, she recalled the smoke, the screams and the suffering of the 2013 bombings.

"I thought that it was it, I thought I was going to die," she said.

The sentencing phase, which began Tuesday, could last up to four weeks.

Prosecutors will try to convince the 12 jurors that there are enough aggravating factors -- including premeditation, the number of victims and a lack of remorse -- to warrant capital punishment.

Defense attorneys will follow the prosecution in calling witnesses, possibly early next week.

They will call for life without parole, portraying Tsarnaev as a confused 19-year-old, frightened of his more radical, older brother.

Tamerlan, 26, was shot dead by police while the pair were on the run.

Jurors were selected in part for their openness to imposing the death penalty, controversial in a state that has executed no one since 1947 and where Catholic bishops oppose capital punishment.

A poll carried out by CNN found that just over half of Americans, 53 percent, said Tsarnaev should get the death penalty.