Innocent until proven guilty is US law, but what is Aruban law? They can detain you without revealing details of what evidence they have. No jury trial, just judges. It looks as if rights we take for granted in the US don't exist on Aruba, or at least are expressed differently. In some countries, you have to prove your innocence. The burden is on the defendant.
Considering that the radio station had people screaming 'innocent until proven guilty', I'm guessing they must work along the same lines.