If...IF this so-called witness is telling the truth that the police was not interested in the specifics of the witness, it is probably because they are simply not reliable.
The police were interested, by their account. They asked her if she'd sign a statement and she didn't want to.
The police were interested, by their account. They asked her if she'd sign a statement and she didn't want to.
Addendum; ASSUMING that this witness is Cutcher. If it's Cutcher's roommate, she signed a statement.