Scare Theater recently did a video on something interesting for once.
Tl;dr: A few years ago, a gas station worker in Mexico allegedly discovered an entire truck full of dead children who were all stacked on top of each other. A rumor then spread saying that the gas station worker was soon also killed, chopped into pieces, and then stuffed into a suitcase with a makeshift sign that basically said "This is what happens to snitches.".
Unfortunately, it's unclear what actually happened. While the worker definitely does seem to have seen something utterly horrific, there's no actual proof that verifies if the truck full of dead children actually existed, or if the worker herself was actually found dead because no one seems to know where she is now.