I thought those were around the pool, not on the beach.
I think Alana said that she was sitting around the HI pool with some of her fellow students and she could see some of her classmates on the beach near the HI pool. But the people on the beach by the HI did not include Natalee or Joran.
I can't remember if it was Dash (the young lady that was on O'reilly)or another one that stated that they were on the beach until 5:30. It could be some were at the hotel pool and some were on the beach.
There is an article that I will try to locate that states that one of the students noticed another student playing around with someone that was (if I remember correctly) not a member of their party out in the water at the beach in the wee hours of the morning.
I believe this was prior to the search where the panties and duct tape were found.
That's the way I remember hearing about it, too.