Now, his ex-lover Joanna Mjadzelics has revealed that she showed Police photographic evidence of the singer abusing a four-year-old child, but nothing was done.
In the image, the girl is holding up a picture frame with cocaine and a razor blade on it.
And despite her calls for help, Joanna says she was repeatedly told to drop it, in order to protect Ian's career.
'It was repeated calls about the same little girl. Every time I knew that my complaints weren't going anywhere with the police I would back it up by going to social services and saying "can't you do anything about this?"'
The Independent Police Complaints Commission is already investigating a detective involved in the case for gross misconduct, and now child protection experts are calling for a further inquiry into how the case was handled.
In her interview with the BBC, Joanna recounted how Watkins described how he was going to rape a two-year-old, and that he actively abused his power over 'super-fans' in order to abuse their children.
Week In Week Out: The Valleys Boy Who Became A Monster will be broadcast on BBC One Wales at 10.35pm tonight.