For those who have said that text messages aren't encrypted, I'm pretty sure this is inaccurate. You can almost guarantee the big social media platforms used TLS encryption on all their data in transit. A quick and dirty packet capture confirmed this, no messages can be seen in plain text. Also, a quick test sending messages from an iPhone with the latest iOS through Burpsuite will cause the app to not work properly. Messages aren't sent or received, and we can see the logs in SSL fatal errors "certificate_unknown". This is even after the cert was installed as a Trusted Root CA. This seems to be evident of SSL pinning, also as expected. There are many variables here, way too many to account for, but I would probably rule out the "This was captured on Airport wifi". With this and the information from the other messages here, I'm personally going to lean towards it was an internal Snapchat flag that alerted law enforcement, or GCHQ has a Snowdenesque backdoor.