Based on the article it seems like the messages were recovered from the local copy stored in the device. Arguably (at least, this is my understanding of OWS's s

Based on the article it seems like the messages were recovered from the local copy stored in the device. Arguably (at least, this is my understanding of OWS's stance on the issue) Signal only really claims to protect in-transit communications. Once the message reaches the recipient, it is up to that individual to secure the local copies of the messages. Signal does have an option to encrypt the local copies, but FDE is the ideal for that