The Labour Party has launched an investigation into the comments and behaviour of one of its MPs following claims he called a constituent an "ugly b****" just months before the election.
Jared O'Mara "categorically denies" the claims made by his Sheffield Hallam constituent Sophie Evans about an incident in March this year.
The announcement of the probe comes a day after Mr O'Mara resigned from his position on the Commons Women and Equalities Select Committee after he joked about having an orgy with members of the pop group Girls Aloud in 2004.
The MP for Sheffield Hallam has also apologised for the offensive comments, which emerged in a report by website Guido Fawkes.
As well as comments about Girls Aloud, Mr O'Mara had claimed Michelle McManus only won Pop Idol "because she was fat" and suggested it would be funny if jazz star Jamie Cullum was "sodomised with his own piano".
Mr O'Mara, who ousted former deputy prime minister Nick Clegg in the June election to become MP for Sheffield Hallam, made the comments in 2004.
Newly revealed online comments from the same period show he also made derogatory remarks about the Spanish and Danes.
However, Labour said the investigation into Mr O'Mara related to the allegations from this year.
"The party is investigating Jared O'Mara MP in relation to comments and behaviour reported from earlier this year," a spokesperson said.
Senior Labour figures branded the alleged comments "unacceptable" and party leader Jeremy Corbyn faced calls to remove the whip from the MP.
Shadow chancellor John McDonnell said the language allegedly used by Mr O'Mara was "unacceptable", while shadow women and equalities minister Dawn Butler said the alleged remarks were "completely offensive".
Speaking to BBC Two's Daily Politics programme, Ms Evans said that some of the comments made to her by Mr O'Mara in March this year "aren't broadcastable".
"There were some transphobic slurs in there, but he called me an ugly b****," she said.
"I just thought 'wow, he's not a very nice man' and just forgot about it.
"I knew that he was involved in politics but I had no idea at the time he was running for MP for Sheff Hallam, which is my constituency."
She added: "I just kind of thought that someone like that couldn't possibly be that heavily involved."
Ms Evans dismissed Mr O'Mara's claims that he had changed his ways in the years since his online posts, which dated to the early 2000s.
She said: "Fair enough for him to have said that about 15 years ago, but he won't even acknowledge something that happened seven months ago."
On Monday, Mr O'Mara apologised for the comments made in 2004, stating he was "deeply ashamed" by them.
"I am deeply ashamed of the comments I made online, which have emerged today.
"I was wrong to make them, I understand why they are offensive and sincerely apologise for my use of such unacceptable language.
"I made the comments as a young man, at a particularly difficult time in my life, but that is no excuse.
"Misogyny is a deep problem in our society.
"Since making those comments 15 years ago, I have learned about inequalities of power and how violent language perpetuates them.
"I continue to strive to be a better man and work where I can to confront misogyny, which is why I'm so proud to sit on the Women and Equalities Select Committee.
"I will continue to engage with, and crucially learn from, feminist and other equalities groups so as an MP I can do whatever I can to tackle misogyny."