[Adder]

True, EXCEPT, [supposedly]he clammed right up after his rights were read.

Guess I would wonder why he was talking THEN decided to stop. If he knew enough to hush up after his rights were read, seems like he would know enough to not talk at all.
Awful lot about this entire case smells really bad....

[ClearCase_guy]

He's been in the country since he was 8.
He is said to have been very Americanized.
I'm assuming he has watched a fair amount of TV.

So, he's talking away to the FBI, giving some valuable information, when some judge walks in and has a conversation with him.
"What?? I have the right to remain silent?? Anything I say can and will be used against me?? Really?? Well, I'm not saying another damn thing!"

I have a hard time with that one.

I find it more believable that the judge carried a direct message from the White House and said, "Shut up or you will be dead in 24 hours." That may not have been the actual words, but I do find that scenario more believable than the supposed scenario that the 19-year-old had never watched a cop show on TV.