According to witnesses she did not go into the water there, they left. So could the blood have been something he planted to prove she did go into the water there. They were seen at 5pm up the beach from where they were and he took off in the opposite direction. Does not leave him time to run back to Baby Beach to snorkel. So his story is unraveling. I would think they have chemicals to test for blood even if it was left over from the Holloway case. My understanding is they are holding the car.
The reason for waiting a month is it's not the USA. LE has to wait for the judge to decide if there was enough evidence to hold him for a crime. If the judge claims there was no crime there is no reason to send off the evidence. They could hold him for 30 days according to their law and then the judge has to make a decision. When the judge decided yes there is enough the evidence was sent on to Holland. Like I said it it different down there and everyone wants to make Aruba fit into what we feel the US would do. They do it differently down there and it does not mean it is wrong. Now if you were in jail you may have a different opinion and wish you were back in the good old USA.
My understanding is the prison has no air conditioning for the prisoners. So yes it would be very uncomfortable for them. But the prison is not that old...maybe 20 years at the most. jmo
Here is a tour from a few years ago.
http://www.bing.com/videos/watch/video/inside-look-at-aruba-prison/6563zyf