Tsarnaev Awake, Answering Questions in Writing

Dzhokhar Tsarnaev has regained consciousness and has been giving investigators written answers to questions, law enforcement sources tell ABC, though it's unclear if he's actually saying anything useful yet. Sources tell Fox News that he will not be formally charged today. The Boston bombing suspect is listed as in serious but stable condition at the Beth Israel Deaconess Medical Center, with neck and throat injuries that prevent him from talking. The shot that injured his throat was fired at close range, sources tell Newsday, and that, combined with the bullet's apparent trajectory, leads investigators to believe that the 19-year-old shot himself in a failed suicide attempt after police discovered his hiding place.

The source says Tsarnaev was mouthing curse words as an ambulance rushed him to the hospital, though it's unclear if they were aimed at his doctors, his captors, or himself. Investigators now believe Dzhokhar may have dealt the killing blow to his brother, Tamerlan, the Boston Globe reports. The 26-year-old had apparently run out of bullets and was struggling with police officers trying to handcuff him when his younger brother sped toward them in a stolen SUV, causing officers to scatter and running over the elder brother, who was briefly dragged by the vehicle, Watertown's chief of police says. (More Boston Marathon bombing stories.)