McKeown was given a warning by police over the alleged incident, which a prosecutor described as "trying to initiate sexual contact with an intoxicated woman".
It is understood police did not believe there was enough evidence to bring a case against him.
It wasn't the first time McKeown, now 37, had come to the attention of authorities. A court heard this year that he was granted a diversion for charges in 2007 relating to an incident in which, drunk, he went into a neighbouring flat, got in bed with a woman and began masturbating.
The Weekend Herald understands Tina told her boss, then-Nelson Mail editor Paul McIntyre, about the alleged incident in 2014 and filed a formal complaint with HR about McKeown two months later. Senior management talked with the woman.
McKeown kept working in the newsroom during this time, covering school sports, and left a month after Tina's formal complaint was filed, former workers told the Weekend Herald.
Tina eventually moved cities before quitting Fairfax.
A lawyer representing Tina said she was unable to comment on the alleged incident but that the situation had a profound effect on Tina's life. Her lawyer said she was assessing the woman's legal options.
That follows McKeown being sentenced in August this year for sexually assaulting a Nelson woman in an encounter when he penetrated her anally with an object without consent, held a knife to her chest and used metal hooks to hold her mouth open.
He was ordered to serve six months' home detention after he was convicted on the unlawful sexual connection charge, as well as supplying and possessing methamphetamine, selling cannabis, possession of an offensive weapon and unlawful ammunition charges.
The Weekend Herald put a detailed list of questions to Stuff, including over McKeown staying at work in 2014 once the allegations were made, if Stuff was aware of his prior police interaction, and what measures were put in place to protect the public as he was covering teen netball and similar school events.
Stuff did not directly address any of the questions.
"As you will know we can't comment on individual employee matters, but I can assure you that we take complaints of this nature very seriously," said Stuff people and culture director Annamarie Jamieson.
She told the Weekend Herald the organisation acted "decisively" to "protect and support" complainants, consulting with them on how they wished to proceed, while doing everything it could to ensure Stuff was a "safe place" to work.
"This is something we are at great pains to stress to staff and our team leaders. We always support and encourage employees to speak up, and help us take action to the fullest possible extent."
When Shannon* (another former Nelson Mail journalist who also worked alongside McKeown and Tina) heard he was charged last year, she said she felt "a deep sense of relief".
She told the Weekend Herald she felt extremely unsafe when McKeown's alleged assault happened and left the media industry because of what she saw as failings in how the media company handled Tina's allegations.
Shannon said she supported Tina after the alleged attack and was named as a witness in her formal complaint to the company.
Although Shannon wanted to help Tina, emails seen by the Weekend Herald show Shannon contacted her union over fears she would be targeted by McKeown because she believed he had been informed of the complaint and was still coming into the office.
"It felt like there were no safeguards in place and I don't think [bosses] knew how to deal with it.
"No one believed, like it kind of felt like we were fighting this uphill battle, like being two naive girls expecting too much.
"He wasn't put on garden leave ... It was totally inappropriate."
McKeown could not be located for comment. The lawyer who represented him in his recent court case was also sent a detailed list of questions but told the Weekend Herald he was "not instructed" on the matter.
The alleged assault of Tina took place at the home of another Nelson Mail worker, Sophie*.
Sophie told the Weekend Herald she felt guilty for not doing enough to support Tina, though she eventually told McKeown's boss of the alleged incident.
As Tina navigated the aftermath of the alleged assault, Sophie said Tina reached out for support but she didn't want to be involved.
"It's terrible, it sounds awful and I feel guilt around not going forward with it but I felt like I'd done all I could."
Sophie said that in her view, Tina did not have the support she ought to have had from her boss or her colleagues.
McIntyre referred all comments to Stuff and declined to answer questions.
Sophie said she was speaking up now because she knew better now.
"[At] the start of your career, you're so worried about doing everything right and so want to climb up the ladder and do your best and you don't want your image tainted, you don't want your reputation gone right at the start of your career. And I think it's kind of sad that that happened.
"Since this time I have been raped. So like these women, I know the lasting effects [sexual misconduct] has on all aspects of a woman's life and that lasts much longer than his pathetic punishment."
* Names have been changed to protect identities
