If my memory is correct Snapchat is not in any way a secure means of messaging when it comes to anything that can be considered illegal. I vaguely recall reading an article a while back about how the snaps are monitored with AI that scans and flags those messages that are questionable. Then a team of humans takes over and views each flagged message, if they find anything that is reportable it is then escalated. The articles focus was on human trafficking, child pornography, and illegal drug activity.
Not a chance I would take honestly. I will look around and see if I can find the original article, or more info for you though.