BOSTON — Boston Marathon bombing suspect Dzhokhar Tsarnaev was charged in his hospital room today with using a weapon of mass destruction to kill — a crime that carries a possible death sentence.
Tsarnaev, 19, was accused by federal prosecutors of conspiring with his older brother to set off the two pressure-cooker bombs that sprayed shrapnel into the crowd at the finish line last Monday, killing three people and wounding more than 180.
The criminal complaint containing the charges shed no light on the motive for the attack.
Tsarnaev was listed in serious but stable condition at Beth Israel Deaconess Medical Center, unable to speak because of a gunshot wound to the throat. His brother, Tamerlan, 26, died last week in a fierce gunbattle with police.
In outlining the evidence against him in court papers, the FBI said Tsarnaev was seen on surveillance cameras putting a knapsack down on the ground near the site of the second blast and then manipulating a cellphone and lifting it to his ear.
After the first explosion went off about a block down the street and spread fear through the crowd, Tsarnaev — unlike nearly everyone around him — looked calm and quickly walked away, the FBI said. Just 10 seconds or so later, the second blast occurred where he left the knapsack, the FBI said.
The FBI did not make it clear whether authorities believe he used his cellphone to detonate one or both of the bombs or whether he was talking to someone.
The court papers also said that during the long night of crime Thursday and Friday that led to the older brother's death and the younger one's capture, one of the Tsarnaev brothers told a carjacking victim: "Did you hear about the Boston explosion? I did that."
The brothers are ethnic Chechens from Russia who have lived in the U.S. for about a decade. Investigators are focusing on a trip the older brother made last year to Chechnya and Dagestan, in a region of Russia that has become a hotbed of separatist politics and Islamic extremism.