Boston Marathon bombing: Dzhokhar Tsarnaev claims brother Tamerlan was ‘driving force’ behind attack, and says the pair worked alone

Boston Marathon bombing suspect Dzhokhar Tsarnaev has reportedly told investigators that his brother was the driving force behind the attack and that the pair were not connected to any wider terrorist network.

A US government source told CNN that the 19-year-old, still in a serious condition in Boston’s Beth Israel Deaconess Hospital, claimed that his brother Tamerlan had organised the bombings because he wanted to “defend” Islam.

The preliminary interviews with Dzhokhar Tsarnaev, in which he responded mostly by writing and nodding and shaking his head, apparently suggests the suspected bombers fall into the category of self-radicalised jihadists acting alone.

The 19-year-old is said to have spoken only once during the interview, and that was to reply “no” when asked if he could afford a lawyer. A public representative was subsequently appointed to represent him.

Tsarnaev is said to be heavily sedated and breathing through a ventilator, although US Magistrate Judge Marianne Bowler found him to be “alert, mentally competent and lucid”.

The news that Dzhokhar Tsarnaev has claimed the driving force behind the attack was his 26-year-old brother comes the day after he was charged with using a weapon of mass destruction to kill three people and injure more than 200 – a crime that potentially carries the death penalty.

He has also been charged with one count of malicious destruction of property by means of an explosive device resulting in death, US Attorney General, Eric Holder, said.

He added: “Although our investigation is ongoing, today’s charges bring a successful end to a tragic week for the city of Boston, and for our country.”

Dzhokhar Tsarnaev is said to be unable to speak after suffering a throat wound, reportedly the result of a failed suicide attempt at the climax of his dramatic arrest on Friday night, when he was found hiding under a tarpaulin covering a blood-stained boat parked on a trailer in a residential garden.

He was said to be so weak from blood loss at the time that officers were able to demand he pull up his top to show he wasn’t wearing an explosive vest and to open his hands to prove he wasn’t concealing a weapon or a detonator.

Tsarnaev was subsequently rushed to hospital where he was said to be in a serious condition after suffering severe injuries and major blood loss.

Unconfirmed reports suggested Tsarnaev may have been hit once or twice by police bullets the previous evening during the fire-fight in which Tamerlan Tsarnaev was killed.

On Sunday police confirmed that Tamerlan Tsarnaev is likely to have died after his younger brother drove a stolen SUV at police officers who were in the process of arresting the 26-year-old.

Over the weekend, Anzor Tsarnaev, the father of the two suspects, said he would fly from Dagestan to the US this week to seek "justice and truth."

His wife reportedly told the Associated Press news agency that Anzor would fly to Boston some time today and that the family wished to take the elder Tsarnaev’s body home to be buried.

Tamerlan visited Dagestan early last year, reportedly evading the attention of the FBI, which had previously questioned him but failed to spot his trip due to a spelling mistake in his name, according to Republican Senator Lindsey Graham.

The US authorities are now said to be waiting to speak to Tamerlan’s US-born wife, Katherine Russell.