I think she was abducted!..When the abductor saw the 1 million pounds up as a reward, they decided to put a ransom on, for her return...of a much bigger sum...This might explain, the parents being so sure that she is being taken care off + them looking for a fund to be set up. They need the money to pay the ransom and they need to pay the legal fees for Neglect.,as I'm sure they will most probably be done for leaving them alone. From what I know, this was an illegal act.
The guy arrested; is just to save face for the portugese police that haven't got the foggiest idea where she has gone....since she was probably swiftly removed on a boad from the harbour.