Peaches Geldof has apologised for tweeting the names of the two mothers whose babies were abused by rock star Ian Watkins.
The daughter of Band Aid founder Bob Geldof posted a series of tweets explaining she had assumed the names were already "public knowledge".
Lostprophets frontman Watkins admitted attempted rape of a baby on Tuesday.
South Wales Police said it was discussing the tweeting issue with the Crown Prosecution Service.
Peaches Geldof is understood to have tweeted the women's names to her 160,000 followers after reportedly reading them on a US-based website.
"I deleted my tweets, however, and apologise for any offence caused," she said.
Geldof said at the time of tweeting she had "assumed" the names she saw on tweets were also published on news websites.
She added: "Will check my facts before tweeting next time. Apologies and lesson learned."
Watkins, 36, from Pontypridd, is due to be sentenced next month after changing his plea shortly before the start of a trial at Cardiff Crown Court.
He was branded a "determined and committed paedophile" after he admitted a string of sex offences, including the attempted rape of a baby.
He plotted the abuse with the two mothers in a series of text and internet messages.
Meanwhile, HM Courts & Tribunals Service has apologised after the names of the defendants were mistakenly included on its court listing website.
"The names were quickly removed from the site and action has been taken to ensure this does not happen again," said a spokesman.
Watkins's former girlfriend Joanna Mjadzelics told ITV's This Morning that singer had said he was going to rape a baby and she had first reported him to the police in 2008, two years after they met.
Ms Mjadzelics said the singer had told her he wanted to sexually assault a baby of an "obsessed" fan and that his fans would "do anything for him".
"I couldn't believe it, I thought he was joking," she told Friday's programme.
Ms Mjadzelics said she felt police didn't believe her when she reported Watkins in 2008.
Two years later, she thought she "must have got it wrong" after no action was taken and she apologised to Watkins.
However, the second time she saw him in 2010, she said he played a "horrific video" on his laptop "and I kicked him out of my room".
Ms Mjadzelics said Watkins had changed in the time she had known him.
"I was in love with that man until 2008 - he's not that man," she said.
The Independent Police Complaints Commission (IPCC) is investigating whether South Wales Police acted "expediently".
The force referred itself to the IPCC.
It has said the delay between Watkins' first and subsequent arrests is one of the things the IPCC will be investigating.
It had received information about Watkins from four other forces in the period before he was arrested, and this will form part of the IPCC's examination.
It is also investigating a detective sergeant from south Wales over alleged inaction regarding reports made to the police.
Chief Superintendent Tim Jones, head of South Wales Police's professional standards department, said: "South Wales Police will fully support the Independent Police Complaints Commission's independent investigation and are committed to responding promptly to its findings.
"In view of the ongoing proceedings it is inappropriate to comment further at this time."
Anyone who has been affected by this case or other cases of child abuse can contact South Wales Police on 029 20634184 or the NSPCC on 0808 800 5000.