Delete attached media when deleting custom post type called "Property".

delete_post_media.php

add_action( 'before_delete_post', 'delete_all_attached_media' );

function delete_all_attached_media( $post_id ) {

  if( get_post_type($post_id) == "property" ) {
    $attachments = get_attached_media( '', $post_id );

    foreach ($attachments as $attachment) {
      wp_delete_attachment( $attachment->ID, 'true' );
    }
  }

}