Let's just get this cleared up right off the bat: no, he didn't personally kill the guy. That said, his revenge did trigger a series of other, unforeseen consequences that ultimately contributed to the bully's premature demise.
Everything started off friendly enough when this dude first started the job, but over time he started to butt heads with a senior employee who wasn't happy that the young dude was starting to become more knowledgeable than him as new software was implemented throughout the company. Dude could have just stayed quiet and retired in peace, but he just had to start some s**t he couldn't finish.
If seeing bullies get their rightful comeuppance is your cup of tea, you'll love these stories of people getting ultimate revenge on their bullies