Boston bombing jury told brothers used al-Qaeda instructions

An FBI explosives expert has told the Boston Marathon bombing trial jury about instructions in al-Qaeda's Inspire magazine that prosecutors contend were used by two brothers to make bombs for the attack.

Dzhokhar Tsarnaev (21) is charged with killing three people and injuring 264 with a pair of homemade pressure-cooker bombs at the race’s crowded finish line on April 15th, 2013.

Edward Knapp, a supervisory special agent with the Federal Bureau of Investigation, read and described the instructions in court that show both how to build pipe bombs and pressure-cooker bombs. He added that the bombs were triggered through a jerry-rigged system involving Christmas lights and parts from remote control cars.

“There are many sites out there ... [that] give you step by step instructions on how to build an IED or bomb,” Knapp testified, using an acronym to refer to improvised explosive devices. The jury also read pages from the magazine that illustrated how bombs were made.

Gunfight

The bombs used in the attack, and others thrown at police during a gunfight in the suburb of Watertown, Massachusetts, were stuffed with explosives taken from fireworks, FBI chemistry specialist David McCollam testified on the 14th day of the trial.

Tamerlan Tsarnaev (26) died four days after the bombing of injuries sustained during the gunfight, which ended when Dzhokhar sped off in a hijacked SUV, running over his brother.

Dzhokhar briefly escaped after the gunfight, prompting a day-long lockdown of most of the greater Boston area while police conducted a massive manhunt. He was found hiding in a boat parked in a backyard late on April 19th, 2013.

He could face the death penalty if he is convicted by the US District Court jury in Boston.

The jury saw a photo of an intact “Big Snow” firework found in Dzhokhar Tsarnaev’s dormitory room at the University of Massachusetts at Dartmouth and another, with the powder removed, found in a backpack taken from the room by a friend of Tsarnaev.

Tsarnaev’s lawyers opened the trial early this month with a blunt admission that their client committed all the crimes of which he is accused.

Rather than trying to prove his innocence, they are trying to avert a death sentence by convincing the jury that Tamerlan was the driving force behind the attacks.

The same jury that determines whether Tsarnaev is guilty will decide whether he is sentenced to life in prison without the possibility of parole, or death.

The bombing killed restaurant manager Krystle Campbell (29), graduate student Lingzi Lu (23), and Martin Richard (8).

Tsarnaev is also charged with the fatal shooting of Massachusetts Institute of Technology police officer Sean Collier three days after the bombing. – (Reuters)