One was a post-doctoral scientist, called X. The lab I was in was asked to take X on by the institute because they had a falling out with another lab, the details of which were not disclosed. A year later, after very poor productivity and various petty issues with other people in the lab, someone checked X's data collection where the original data was available on the instrtument, and found that it was all made up. Subsequently the previous lab investigated, and a paper X published as first author was retracted. Turns out in the previous lab there were also concerns about data fabrication and many other problematic interactions before the fraud was discovered. Also turns out X left another lab before this under similar circumstances.

Another was a well established Professor 'P' with a very large number of published papers, who continued to publish multiple papers at a high rate. There had been doubts for years due to data that seemed too cute and the fact that P always took the data and made the final figures in the paper themselves. P was finally caught out when a paper included data which could not possibly have been collected, and was outright fabricated.

It is worthing nothing that both P and X left the institute without disciplinary action beyond employment termination and signing an NDA. One of them is in another city, getting government grants and doing just fine. Everyone in the know doesn't trust any of their papers of course, but I guess that doesn't include whoever reviews their grants.

None of these are 'good people gone bad'. They are are flawed individuals with no integrity and sociopathic personality traits, and they waste a lot of decent people's time dealing with their actions.