Not quite. They were using an app developed by the police as a honeypot. Someone else had even discovered this and blogged about it[0]. If they had used email and PGP they likely wouldn't have been caught in this way. 3-letter agencies are not going to use their trump card of backdoored OS or hardware to catch drug runners.
[0]https://webcache.googleusercontent.com/search?q=cache:PwQXt6...