"And we don't know if we'll ever be able to question the individual," he said without elaborating.
U.S. Senator Dan Coats, a member of the Intelligence Committee, said it was questionable whether Tsarnaev would be able to talk again.
"The information that we have is that there was a shot to the throat," Coats told the ABC program.
"It doesn't mean he can't communicate, but right now I think he's in a condition where we can't get any information from him at all," said Coats, an Indiana Republican. (Continues)