Unless it's encrypted anything on flash memory should be recoverable. Nothing every gets truly overwritten on that technology. Maybe they could try to overwrite every address 5 times but that would be painstakingly slow to do to 30+ phones. I doubt they did that. Edit: Didn't read the last part. Ok they wiped it good. I bet it took a whole team.

Unless it's encrypted anything on flash memory should be recoverable. Nothing every gets truly overwritten on that technology. Maybe they could try to overwrite every address 5 times but that would be painstakingly slow to do to 30+ phones. I doubt they did that.