There's clearly a lot more to the story than the police are saying. They're drip feeding information. I guess the rape conviction is already in the public domain, so that's now been released in an attempt to get people snitching.
The father's appeal today included:
"I beseech you to find a way to turn yourself and your wee one into the police as soon as possible so you and he or she can be protected. Only then can a process of healing and recovery begin."
Why does she need to turn herself in to the police? Is he (both of them?) wanted for a crime, but that information hasn't been released?
I'm guessing the are either human rights privacy issues or a fear of prejudicing a trial.
The police don't normally name people until they've been charged. Until they're found, they can't be charged.