delete_post hook problem in WP 3.2.1

I’m trying to delete all attached files before a post is deleted.
But hook called my function after a post is deleted.

There is my code:

function delete_post_children($post_id) {
    global $wpdb;
    if (get_post_type( $post_id )=="property") {
            $ids = $wpdb->get_col("SELECT ID FROM {$wpdb->posts} WHERE post_parent = $post_id AND post_type = 'attachment'");

    foreach ( $ids as $id )
        wp_delete_attachment($id,true);
    }

}
add_action('delete_post', 'delete_post_children');

This problem appears, after i updated to WP 3.2.1

Can anyone help me ?

Thanks!