Media playback is unsupported on your device

How could Lostprophets singer Ian Watkins abuse for so long?

18 December 2013 Last updated at 20:49 GMT

Lostprophets singer Ian Watkins has been sentenced to 35 years for a string of child sex offences including the attempted rape of a baby.

The police had information on him as far back as 2008 but he was not arrested until last year.

So, why was Watkins able to go on abusing children and collecting images of his abuse for so long?

One officer from South Wales Police is under investigation for gross misconduct.

Now it has emerged the force itself - and two others - are to be investigated by the police watchdog.

Caroline Evans reports for BBC Wales Today.

Ian Watkins sentenced to 35 years