Boston Marathon bomber sentenced to death penalty for killing three and injuring 264 in blast

Boston Marathon bomber Dzhokhar Tsarnaev has been given the death sentence following his conviction for using a weapon of mass-destruction to kill three people.

The 21-year-old was found guilty last month of murder and injuring 264 in the 2013 attack after planting two home-made bombs along with his older brother near the finishing line of the race.

He had faced a sprawling 30-count indictment, with 17 of the charges carrying the death penalty.

The jury who convicted him last month sat through a second hearing to determine if he should be put to death or spend the rest of his life in Colorado’s supermax prison.

The unit called the Alcatraz of the Rockies houses some of the world’s most feared terrorists as well as British shoe bomber Richard Reid.

Following his terrorism conviction hook handed cleric Abu Hamza is also expected to be sent to 'Administrative Maximum Facility' shortly.

But after almost 15 hours over three days of deliberation all 12 - seven women and five men - unanimously agreed he should be sent to the death chamber.

Of the 17 charges that carried the death penalty the jury said they were unanimous on six of counts that Tsarnaev should be administered a lethal injection.

Their verdict will now spark a series of appeals with US legal experts saying they would at least four years before they were exhausted.

As the verdicts were read out Tsarnaev showed no emotion as several people in the public gallery broke down in tears.

After Judge George O’Toole told the jury: “You can, you should, be justly proud of your service.”

The defence hoped to save Tsarnaev's life by pinning most of the blame on his radicalised older brother, Tamerlan, who was killed as their tried to escape capture in the days after the April 15, 2013 attack.

At the 11th hour they called Sister Helen Prejean an influential opponent of capital punishment who was made famous after being portrayed in the film "Dead Man Walking”.

Prosecutors however painted Tsarnaev as an equal partner in the attack and so heartless he placed a bomb behind children.

During the death penalty hearing jurors were shown a picture of Tsarnaev “flipping “ his middle finger after his arrest.

He made his defiant gesture to a security camera in his jail cell as he waited to arraigned in court three months after the bombing.

Boston prosecutor Nadine Pellegrini told the court the photo showed Tsarnaev "unconcerned, unrepentant and unchanged" despite his crimes.

Eight-year-old boy Martin Richard, 23-year-old Lingzi Lu and 29-year-old Krystle Campbell were killed - and 16 others were seriously wounded - when the two shrapnel-packed pressure-cooker bombs were detonated.