Anybody thinking they'd never give a false confession under any circumstances, is greatly underestimating the psychological effect a skilled interrogator has- especially on kids that age. It was probably a scare tactic of some sort- like the threat of a much harsher punishment if they
didn't confess.
Those 5 should never have been denied access to a lawyer.

I'd just whip it out and start beatin' it right there in the interview room. The detective would be so insanely jealous at the size of my cock that he would be unable to proceed with the interrogation.