Twitter stores Direct Messages even after users opt to delete them
When you or other participants in a conversation elect to delete a message, you might think that means that the message is gone completely. In Twitter's case at least, this isn't so.
Users can confirm that Twitter has retained these messages by simply downloading the archived data from their account settings page.
Security researcher Karan Saini confirmed with TechCrunch that direct messages sent and received to or from accounts that have been deactivated or suspended are not only still accessible, but can also be used by Twitter in cooperation with law enforcement.
In that same TechCrunch report, a Twitter spokesperson commented that the social network is "looking into this further to ensure we have considered the entire scope of the issue.” This is a far cry from any sort of commitment to changing this practice, and does not ensure that anything will change in practice.