I'm confused. Did Croes identify the "mystery person"? Is that who called Croes?
The mystery person who contacted Charles Croes about his Cell Phone Rental service was most likely the undercover US DEA Agent that was on the island and who hooked up with the chaperone that stayed behind after Natalee was discovered missing. We know that a undercover DEA agent help out greatly during the first few days of this case.
I'm typically confused over the whole phone message story....as far as I know, we don't know who the message was from or to whom it was made.
On LKL last night or maybe the NG show, a reporter said that the Equasearch people will be searching close to the lighthouse today....northern tip of the island.
I see brigette answered your question, probably better than I could. :-D