Sorry, this one is very, very long... so if you have the time, read on... I
got a colleague fired... and he thoroughly deserved it!
He cjoined our company while we were working on a very large project (think a 3 year engineering project). He was slotted to work under me on my team but he kicked up a fuss and demanded to be hired at an equal level to me. Fair enough, his cv was very impressive and we needed an expert in his "area". Within weeks it was obvious he had BS'd his way into the position, he was in way over his true skill level and I learned unofficially from people at his previous company that he had quit just in time to avoid being fired. You cannot imagine the size of this guy's ego though! He genuinely thought he was brilliant and everything he screwed up was someone else's fault - in fact I found out he was blaming me for some of his messes, in areas I had zero involvement in! That's when I realised this man had to go...
We have excellent project management tracking software and good programming records, so it became clear that he was deleting records of bad code that he had submitted to make it harder to trace the origin of bugs appearing in code he was ultimately responsible for. Despite all this he still BS'd brilliantly to upper management and conveniently created some friction with another colleague to give him an active complaint to lodge with HR making it very difficult to try firing him.
Our team was miserable because of his terrible work performance and the active problems he was causing in our work product, causing delays. I was very stressed and seriously thinking of looking for a new job, so I logged onto LinkedIn and casually checked BS man's profile (curious about all the professional BS contained in his profile). I quickly noticed that he had a fully updated profile (he was obviously job hunting - he was at least smart enough to know that he wasn't going to last much longer at our company) and in his career achievements etc.. at our company he totally lied about being responsible for senior elements of the project that he wasn't senior enough to work on and most importantly he revealed proprietary information about our project - a massive 100% fireable offense. I took a screen shot just in case and the next morning I went straight to our boss and told him what I'd seen. BS man (I assume) was alerted by the notification of me viewing his profile and when our boss checked it the next morning the BS lies and proprietary info had disappeared - then I showed him my screenshot and he was gone by lunchtime.
This was years ago now and our industry isn't that big, I still hear about him every now and then, still bouncing around from company to company. His name rhymes with "train" so in our team he is referred to as the "Blain-wreck"* still...
*Not his actual name.
Nope, still don't feel bad at all. That man was awful, he lied and got colleagues into trouble to cover himself with hesitation because his ego wouldn't allow him to admit that he couldn't perform the tasks at the level he thought. I laugh about it now but it was probably one of the most stressful times in my career.