Paedophile rock star Ian Watkins could have been caught nearly four years earlier if South Wales Police had investigated the case properly, the Independent Police Complaints Commission has said.
South Wales Police officers missed a series of chances to stop the Lostprophets singer's abuse of children in the years before he was arrested.
Watkins was jailed for 29 years in December 2013 after admitting sexual offences, including the attempted rape of a fan's baby.
It came after his arrest in September 2012 following the execution of a drugs warrant at his Pontypridd home, which also resulted in computers, mobile phones and storage devices being seized.
The IPCC said that prior to that, between 2008 and 2012, officers had failed to adequately action eight reports and three intelligence logs from six individuals about Watkins' activities.
String of accusations
One of these was from Watkins' ex-girlfriend Joanne Mjadzelics, who reported him in December 2008 and was interviewed on video three months later.
She told officers she had a message on her mobile phone from Watkins saying he wanted to sexually abuse children.
The report said the phone was not examined because her report was thought to have been "malicious".
IPCC commissioner for Wales Jan Williams said there was no evidence showing the inaction was due to Watkins' fame but it was instead officers' assessment that Ms Mjadzelics lacked credibility.
But Crimestoppers reports from 2010 and reports from two witnesses that year and in 2012 did "not appear to have been progressed", despite supporting Ms Mjadzelics's account.
Ms Williams said that the failures involved a small number of officers who had shown a "lack of open-mindedness and professional curiosity".
"This continued until 'the right type of complainant' came along," she said.
The investigation also found poor record keeping and retention; poor management of intelligence; weaknesses in safeguarding and supervision; a lack of rigour in progressing investigations; the handling of third party reports as opposed to those from victims; and an inadequate approach to cross border investigations.
Assistant Chief Constable Jeremy Vaughan said the force "entirely accepts and regrets" the failings highlighted by the report.
He added: "South Wales Police failed to listen and properly investigate information about Watkins' offending behaviour, for this we are truly sorry.
"The review instigated as a result of Watkins' arrest led to significant changes being made to the way we investigate crimes of this nature.
"I am confident that police officers and staff who work in this very challenging area care deeply about the service they provide to victims.
"I know it is difficult taking that first step in reporting child abuse and that people coming forward need support but we urge anyone with concerns about a child or young person to get in touch with us immediately."
The news comes just days after the IPCC made similar criticisms of South Yorkshire Police's handling of the case, saying three officers could have faced charges of gross misconduct but, as they had all retired after 30 years, no action could be taken.