One of her competitors, she has now revealed, laced her national costume with pins, which stuck into her skin and made her wince as she walked on to the stage in the competition last month.
Her outfit was perfect for concealing the handiwork of her mysterious and apparently jealous assailant - it was a swirling flamenco-style dress decorated with Aboriginal-style art.
Ms Campbell, 19, from Queensland's Gold Coast, finished third in the Las Vegas contest which drew beautiful women from 82 other countries.
'Not pointing fingers': Jesinta does not know which smiling assassin stabbed her
And while Ms Campbell was ready for some bitchiness and backstabbing among her competitors, she did not expect the kind of dirty tricks played on her.
First, she had to put up with giggles and sneers when she dressed in her incredible outfit, made up of high-heeled Ugg boots, an Aboriginal-art-styled one-piece swim suit and that brightly coloured flared dress.
Then came the physical pain.
'I put it on just before I was due to go out on parade, but I felt these sharp pains when something stuck into my back,' she told Sydney's Daily Telegraph.
'I took the top off and found all these pins had been stuck into it.
'I didn't have any injuries or marks, but I didn't have much time to take them out and get it back on because I had to be out there.
'The sabotage was a bit harsh, but you have to laugh at these things and not take it too seriously. And it did give me a story to tell when I got home.'
But who was it? Who was the jealous culprit who would stoop to such a dastardly act?
'I'm not pointing any fingers,' said Ms Campbell.
Then she admitted that contestants from Mexico, Central and South American countries and the Philippines were 'extremely competitive'.
Miss Mexico, Ximena Navarrete, was crowned Miss Universe. And Jamican Yendi Phillipps came second, ahead of Ms Campbell.
'Winning is so important for those girls because they become queens in their country and are worshipped if they win - and it changes everything for ever for them,' Ms Campbell added.
'There were 82 other girls there and I can't narrow it down, so it's a mystery to me.'
At least the contestant from Great Britain, Tara Hoyos-Martinez, is off the hook.
'I know who didn't do it,' continued Jesinta.
'My best friends were the girls from Ireland, Belgium, Great Britain and Guam and I know they wouldn't have done that to me.'
The crown was won by Miss Mexico, Jimena Navarrete, while the equally competitive Miss Philippines, Maria Venus Raj, was said to have blown it during the Question and Answer part of the programme.
If Ms Campbell had listened to the pleadings of animal rights groups, she might not have worn those high-heeled Uggs.
The groups claimed they were cruel and unethical because they were made from Australian wool sourced from sheep which have been mulesed - a painful process that involves stripping the sheep's wool-bearing skin from its rump to prevent disease from flies.
But Ms Campbell was determined to go ahead with the entire outfit, describing it as 'incredible' and 'something I am really proud to wear - I feel magnificent in it.'
She has no plans to pursue a career as a model or even enter another beauty pageant.
Instead she hopes to work as a fashion and entertainment television reporter and continue with charity work.
Miss Australia: Jesinta Campbell poses while competing in Miss Universe 2010 - but who stabbed her in the back?
Lady in red: Ximena Navarrete of Mexico (R) won, while Jamican Yendi Phillipps (L) came second in Miss Universe 2010
