Getting deleted messages in rest api call

rest
api

#1

Eventhough i have deleted the conversation in my twitter handle. I can get those message via these two api call.
https://dev.twitter.com/rest/reference/get/direct_messages/sent
https://dev.twitter.com/rest/reference/get/direct_messages

Both in sent messages api call and received messages api call.
Please anyone give the clarification for this?