Why was Sonny killed?

I'm curious to know, what led to the tragic demise of Sonny? Was it a personal vendetta, a business dispute gone wrong, or perhaps a misunderstanding that spiraled out of control? Did he have any enemies that might have had a motive to harm him? And what measures, if any, were in place to protect him from such a fate? It's a sad and perplexing situation, and I'm eager to understand the reasons behind it.