How to distinguish the source of a comment?

Hi Zendesk Support,

When we are calling Zendesk API to interact with our system:

• When our end-user sends comment to our system, our system call Zendesk API to create Zendesk ticket or add new comment to an existing Zendesk ticket;
• The Support representative will view the comment on Zendesk platform and add comment via UI to response.

My question is: how do we know which comment were added by end-user, which comment were added by Support representative?

I know by click `Events` on the ticket page we can see the difference; however, the `Events` are invisible by default. What is the  better way to distinguish both sources?

Here is the link to view the ticket snapshot that I captured from Zendesk platform:

https://docs.google.com/document/d/1-zefsCGOgFIfr7kmW8Kx0BrUJwsq9GWgLO30_XOro6w/edit

(It seems image upload does not function when creating the post.)

Thanks,

Junsheng from Wunderkind