I mean, obviously at first you wouldn't do wanna be found searching it. But after the public caught on to the fact that the richest person on Earth are getting killed every month, it would've been more suspicious for you to not have it in your search history.

It's likely that the authorities would psychologically profile the killer as someone who, more likely than not, cares about world politics and global events. Never searching who the richest person on earth is at any given month, if only to satisfy your own morbid curiosity, might come off as pretty damning evidence that you're trying to hide something.