Boston suspect charged with using WMD, faces death penalty

The lone surviving Chechen-origin Boston bombings suspect has been charged with conspiring to use a "weapon of mass destruction" and faces death penalty, as a criminal complaint filed by the FBI said that he apparently used a cell phone to trigger the pressure cooker bomb.

The FBI filed the complaint against 19-year-old Dzhokhar, as he was produced before a district court which temporarily was his hospital room where he is being treated of injuries.

In the complaint yesterday, the FBI alleges that the suspect appeared calm while there was chaos all around after the blasts at the finish line of the marathon on April 15.

Dzhokhar was charged with conspiring to use "weapon of mass destruction" and faces death penalty if convicted.

The court fixed May 30 for Dzhokhar's first hearing in Massachusetts District Court.

In the 10-page complaint, FBI special agent Daniel Geneck gives the sequence of events and the information to sufficient to establish the requisite probable cause. "It does not include each and every fact known to me," he said.

Dzhokhar's brother Tamerlan Tsarnaev, 26, was pronounced dead on Friday after suffering shrapnel and bullet wounds in a gunfight with police. Dzhokhar was later arrested in connection with the bombings that killed three people and wounded 180 others.

Based on the information obtained from the security cameras, Geneck said, the two suspect - Tamerlan, 26, and Dzhokhar- were first spotted near the bombing site 11 minutes before the first bomb explosion.

While Tamerlan was wearing a dark-coloured baseball cap, sunglasses, a white shirt, dark coat and tan pants, his brother was wearing a white baseball cap backwards, a gray hooded sweatshirt, a lightweight black jacket, and dark pants.

Thereafter, the two were seen moving towards the Marathon finish line, which was occupied by thousands of people.

At some point Dzhokhar appears to look at his phone, which is held at approximately waist level, and may be manipulating the phone, Geneck said."Approximately 30 seconds before the first explosion, he lifts his phone to his ear as if he is speaking on his cell phone, and keeps it there for approximately 18 seconds. A few seconds after he finishes the call, the large crowd of people around him can be seen reacting to the first explosion," the complaint said.