Dzhokhar Tsarnaev, the surviving suspect in the Boston Marathon bombings, has been unable to speak, but has been responding to questioning from authorities, according to reports.

Since being apprehended on Friday, Tsarnaev has been too badly injured to speak, after receiving a gunshot wound to the throat, but CNN reports it was told by a senior federal official, that he has been communicating in writing as he has been questioned since Sunday.

CNN’s Holly Yan and Chelsea Carter write:

Neither source would say what, if anything, Tsarnaev has been telling investigators about his alleged role in the bombing that killed three and wounded more than 170 a week ago Monday.

But if he’s talking, perhaps authorities will learn some valuable information that could potentially prevent further attacks.

According to The Boston Globe, Tsarnaev’s brother, the other suspect, was actually killed by Dzhokhar running him over, rather than the police shootout that transpired. This graphic photo of his corpse shows the wounds.