least four people. >> reporter: people have grown up thinking a prescription pills are safe. whatever it is, you've got pills for it. so we all trust the pills. especially when they're young. looks legit. >> reporter: you didn't know to say to alex, one pill could kill you? >> exactly. we had no idea that one pill would kill him. we had no idea about fentanyl. we talked to our kid. if talking to alex was all it took, that kid would have lived forever, but we weren't talking about the right thing, because we didn't know about it. >> reporter: and where did a 14-year-old, a child, get illegal drugs? >> he told us he had connected with his dealer through snapchat. >> reporter: buying drugs on social media is so common that the dea has worked to figure out which emojis teens use to make the purchases. >> if you put a cookie, rocket, and candy bar together, it looks innocent. but what i just said is i received a large shipment of highly potent xanax bars. >> so these two together mean xanax? >> yep. and this means bring it to school. >> yep. >> reporter: snapchat says it