The 15-year-old was invited to the party on Saturday night, to watch the big fight between Mayweather and Pacquiao.
Dozens turned up to the bash at an Edinburgh flat, including several underage girls, alongside a footballer and boxer.
Our sister paper The Daily Record, which reports the investigation, has chosen not to name the sportsmen, as it understands they were unaware of any illicit sexual activity.
The 15-year-old went to a bedroom with an older man where they had sex – while other party-goers recorded them on mobile phones.
But the girl was left stunned when the sexually-explicit video of her with the older man was later shared across social media.
Concerned members of the public alerted the Daily Record to the video and images of the naked girl on the internet.
A source close to the girl said: “The flat was rented for the guys, who call themselves the Flame Gang, to watch the boxing.
“A whole load of girls were also invited but most of them were about 15.
“A lot of drink was taken and the girl herself said she didn’t know she was being filmed. It’s outrageous. Loads of them had their phones out taking pictures and videos of them in the bed.”
We flagged up our concerns to Police Scotland who immediately launched a major investigation into the allegations.
Shockingly, the girl received a backlash from some social media users when she complained about the video.
In message online she confirmed her age said that she was ‘hurting’ because 20-year-olds had taken advantage of her.
Yet she was inundated with replies from other teenagers mocking her outrage at the film being circulated.
Many of the disgusting responses are too explicit to print but one girl replied: “Didn’t seem that bothered when you were being recorded though?”
Another woman tweeted: “Why would you actually let folk video you having sex and not even give a ****?? Mate.”
And a teenage girl said: “So bothered of getting taken advantage of that you continued to get ******* when cameras were pointing at you.”
Another called the girl vile names and suggested she was trying to ruin lives because the video was on a public forum.
The man, who has been identified on Twitter as the person she had sex with, was openly joking on the internet about taking up a job with a porn site.
He was encouraged to brag about his exploits by other users including one woman who said: “My boy knew you could do it.”
The footballer was named by dozens of people on the micro-blogging site and one cheeky user tweeted he wanted money from him or he was informing his club about the party.
However, one outraged user wrote: “Spice boys thinking they are somebody because they kick about with someone who plays for a team and **** who **** 15-year-olds.”
Last night Police Scotland said they were investigating the footage.
A spokesman said: “Any information we receive in relation to sexual offences will be thoroughly investigated and we welcome information from the public in connection with crimes of this nature.”
Source: uk mirror