A media investigation into the allegations of rape featured in Lena Dunham's recently-released memoir has refuted the claims of sexual assault made by the Girls creator.

The writer, actor and director dedicates a chapter of her book, Not That Kind Of Girl - for which she received a reported $3.7 million advance - to a boy she met at Oberlin College in Ohio identified as 'Barry', who she alleges raped her one night after a party.

The 28-year-old admits in the tome to drinking alcohol and taking Xanax and cocaine before inviting Barry back to her on-campus apartment, but says the encounter quickly turned aggressive, and that Barry twice removed the condom during intercourse without telling her.

'I never gave permission to be rough, to stick himself inside me without a barrier between us,' she wrote.

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Rape claims: In her memoir Not That Kind of Girl, Lena Dunham (seen here in New York on December 2) alleges she was raped in college. A new media investigation claims there is no proof of the man she describes

'I never gave him permission.

'In my deepest self I know this, and the knowledge of it has kept me from sinking.'

Dunham's description of Barry is similarly explicit, explaining him as a 'mustachioed campus Republican' with a 'mustache that rode the line between ironic Williamsburg fashion and big buck hunter', who hosted a radio show called Real Talk With Jimbo, worked in the library stacking shelves and 'wore purple cowboy boots'.

She also said that he once punched a girl 'in the boob' at a party and, following a consensual sexual encounter, another girl woke to find blood spattered all over the wall 'like a crime scene'.

Furthermore Dunham does not state that 'Barry' is a pseudonym, as she does with other names that appear in her book.

An investigation by John Nolte from Breitbart News undertaken at the Oberlin campus, which was published Thursday, concluded that the 'Barry' Dunham describes is a 'ghost', and that no such person appeared to exist at the college during the years she studied there.

'In fact, we could not find anyone who remembered any Oberlin Republican who matched Dunham's colorful description,' Nolte wrote.

'Under scrutiny, Dunham's rape story didn’t just fall apart, it evaporated into pixie dust and blew away.'

Scene: It is believed the rape Dunham describes in her book took place at Oberlin College in Ohio (pictured) in the winter of 2005 following a party

The Breitbart report followed an attack on Dunham by The National Review's hard-right columnist Kevin Williamson, who said she was 'grossly irresponsible' for publishing the rape claim in the first place.

Williamson said he spoke to a Barry who was a prominent Republican that attended Oberlin and that has been hounded by the media since the release of Not That Kind Of Girl in September.

This Barry told Williamson he has never met Dunham and did not have any kind of relationship with her.

He said the fact his name is Barry and that he is a Republican who went to Oberlin is 'the 'most unfortunate coincidence of my life'.

The man, who is married with kids, said he is petrified that his full name is going to be published.

Williamson then wrote of Dunham: 'It is at the very least the deployment of weaponized celebrity without any concern for collateral damage.

'I have my doubts about whether the encounter Dunham describes actually happened at all; in her memoir, she writes about presenting anecdotes from other people’s lives as her own.

'But, for the record, the man to whom I spoke does not believe that Dunham intended to refer to him.'

The Breitbart investigation, which describes Dunham as 'one of the most powerful and influential women in America', included the account of Williamson's 'Barry'.

It notes that friends of his laughed at the suggestion of him ever having a moustache and that other details given by Dunham also didn't fit.

Nolte then goes in search of someone else that might fit the description.

He deduces the alleged rape occurred in winter 2005.

A search of the campus newspaper archives and Oberlin College graduation announcements did not find any Barry - other than the one Williamson spoke to - who graduated or attended Oberlin College in 2005, 2006, or 2007.

Massive publicity tour: Lena Dunham meets fans and signs copies of her book 'Not That Kind Of Girl' at Waterstones in London on October 29, 2014

A further search of the campus for someone not named Barry but who fits the description given by Dunham also showed no results.

There was no proof of a radio show called Real Talk With Jimbo, he said.

'Nevertheless, no amount of digging could verify even a single detail of Dunham's rape claim,' Nolte wrote.

The report criticizes Dunham for pointing the finger at this one Barry in such a public manner, as opposed to reporting what happened to her to the authorities.

Dunham has not responded to the Brietbart News piece.

Calls to Random House, the publisher of Not That Kind Of Girl, and to Dunham's literary agent made by MailOnline were not immediately returned on Thursday.

Dunham did however react to Williamson when his piece was published last month.

She took to Twitter to defend her story.

Love: Dunham is seen here at the 2014 Golden Globes with her boyfriend, musician Jack Antonoff

'Some men are enraged by stories of sexual assault that don't have clear cut villains, pimps or men with guns,' she wrote.

'That's because these stories force them to ask hard questions about their history with consent.

'Well, we all have to ask hard questions. Grow the f--- up.

'And I have some news for certain 'news' outlets. No matter how much you thump your keyboards with your meat hands we will not stop talking.'

This is not the only controversy to come from Dunham's tome.

The New York native cancelled several appearances on her book tour after being accused of molesting her younger sister as a child.

In one chapter of the book she describes how, as a seven-year-old, she experimented with her sister Grace, who was one at the time.

'One day, as I sat in our driveway in Long Island playing blocks and buckets, my curiosity got the better of me,' Dunham wrote.

'Grace was sitting up, babbling smiling, and I leaned down between her legs and carefully spread open her vagina.'

The accusations were mostly spearheaded by Williamson, who said her behavior was child abuse.

Dunham came back swinging, writing on Twitter: 'The right wing news story that I molested my little sister isn’t just LOL- it’s really f---ing upsetting and disgusting.

Family: Dunham was accused of molesting her younger sister Grace (pictured) by two media outlets following a controversial chapter in her book, where she admits to experiment with her sibling as a child

'And by the way, if you were a little kid and never looked at another little kid’s vagina, well, congrats to you.

'Usually this is stuff I can ignore but don’t demean sufferers, don’t twist my words,

'I told a story about being a weird 7 year old. I bet you have some too, old men, that I’d rather not hear.