Dzhokhar Tsarnaev, the surviving brother implicated in the deadly Boston Marathon bombings, has been charged with using weapons of mass destruction to kill people, a federal crime which is punishable by death, the Justice Department said.

The Justice Department said on Monday that 19-year-old Dzokhar Tsarnaev had been charged with one count of using a weapon of mass destruction and one count of malicious destruction of property resulting in death.

The charges are punishable by death, life in prison, or any other indeterminate prison sentence, the department said in a statement.

According to the affidavit of Special Agent Daniel R. Genck, a Massachusetts Registry of Motor Vehicles photograph of Dzhokhar Tsarnaev bears a “close physical resemblance” to video images of “Bomber Two,” who was seen near the Boston Marathon Finishing line at the time of the attack.

The agent continues that the footage reveals the suspect using a cellphone after setting down a knapsack near the blast site.

“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 does not elaborate whether Dzhokhar Tsarnaev allegedly used his cellphone to detonate the explosive device, though it describes as “calm” as those around him are in a state of“bewilderment and alarm.”

On Monday, during a bedside court hearing in the Beth Israel Deaconess Medical Center Dzhokhar Tsarnaev has been read his Miranda rights by a US judge. He also reportedly told investigators that he and his brother worked alone, and that Tamerlan had organized and led the attacks out of a drive to “defend” Islam.

Boston Bombing:Tamerlan and Dzhokhar Tsarnaev they Had Religious Motive

The brothers, ethnic Chechens from Russia who had been living in the US for about a decade, practised Islam.

Two US officials said preliminary evidence from the younger man’s interrogation suggests the brothers were motivated by religious extremism but were apparently not involved with Islamic terrorist organisations.

Dzhokhar is said to have communicated with his interrogators in writing due to his injuries.

They said they were still trying to verify what they were told by Tsarnaev and were looking at such things as his phone and online communications and his associations with others.

In the criminal complaint outlining the allegations, investigators said Tsarnaev and his brother each placed a backpack containing a bomb in the crowd near the finish line of the marathon.

The FBI said surveillance-camera footage showed Dzhokhar manipulating his mobile phone and lifting it to his ear just moments before the two blasts.

After the first explosion, a block away from Dzhokhar “virtually every head turns to the east … and stares in that direction in apparent bewilderment and alarm”, the complaint says.

Dzhokhar Tsarnaev “virtually alone of the individuals in front of the restaurant, appears calm”.

He then quickly walked away, leaving a backpack on the ground; about 10 seconds later, a bomb blew up at the spot where he had been standing, the FBI said.

The FBI did not say whether he was using his mobile phone to detonate one or both of the bombs or whether he was talking to someone.

Meanwhile, Kazakhstan’s Ministry of Foreign Affairs issued a statement saying two foreign nationals arrested on Saturday in the Boston area on immigration violations are from Kazakhstan and may have known the two marathon bombing suspects.

The foreign ministry said US authorities came across them while searching for “possible links and contacts” to Dzhokhar Tsarnaev. Their names have not been released.

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