The Victor Ninov situation is one of my favourite cases of scientific fraud because it's rare to see so straightforward an example of someone being brought low by their own hubris.
Like, okay, faking the synthesis of a previously unobserved element: it's one of the few varieties of scientific fraud that actually has a clear gameplan for getting away with it. The physical properties of unobserved elements are, in principle, predictable, and there are only so many ways to go about synthesising them. If you do your homework, it's not outside the realm of possibility that your claimed results will end up being at least mostly consistent with the results of subsequent legitimate efforts to synthesise that element, and any minor discrepancies will end up being dismissed as statistical anomalies and/or the product of sloppy experimental design. It's by no means an easy game to play, but it's a game you can conceivably win.
And Victor Ninov did it. He rolled the dice and he won – twice. His fabricated results for elements 110 and 112 were corroborated by later work, and nobody noticed that his actual data was a crock of shit. He got away with it as cleanly as he could have hoped. It was only the third time he tried it, with element 118, that he biffed it and claimed results which nobody could replicate, and this is the only reason his earlier frauds were discovered. If he'd quit while he was ahead, it's likely the first two incidents never would have come to light.
Like, they say the third time's the charm, and buddy here learned the hard way that sometimes, the opposite also holds true.