What API will read and delete the incident? Will deleting incdient delete the attachment too?

Content

Team , I am new to RNT so i am looking for an answer from the forum.

In order to manage the database and file storage, my manager is asking me to use the API to read the incidents and it's related attachments for a regular interval(example: anything older than 3 years) to our local storage for our own reporting and delete the incident and related attachments. 

We want to know what API read and delete the incident? When i issue a delete will it delete the attachment as as well so that we can reclaim file storage as well ?