How Is Insider Trading Tracked/proven?

If insider trading is done under set guidelines then its not illegal and obviously not tracked by any jurisdiction. So, here we are talking about illegal insider trading. In order to track illegal insider trading, SEC has some regulations, which says it is illegal when, “buying or selling a security, in breach of a fiduciary duty or other relationship of trust and confidence, while in possession of material, nonpublic information about the security.” In order to track it, market surveillance activities take place in which SEC uses sophisticated tools to detect illegal insider trading, especially around the time of important events such as earnings reports and key corporate developments.
Adding to that, insider trading is also revealed through tips and complaints from sources such as unhappy investors or traders on the wrong side of a trade. Also, the tendency to leverage up the inside information as much as possible is another vulnerability that makes it easier to detect insider trading.