This is where it all becomes quite frustrating - The Times apparently reported that three notes were found by the police, but the police have never confirmed it. In other reports it is said that her bag, wallet (with cash) had been found - but again no official confirmation.
The notes, supposedly addressed to her friend, parents and another friend, would've been handed over to her family., If they didn't want to disclose what they said, then the police also couldn't say anything.
JMO - but unless there's an outright denial then you can *usually* hazard a guess that it's true.