[dba-SQLServer] Audit table - How to capture user who deleted record

Hello everyone,
I'm creating an audit table for our application. I had no problem with
the trigger for an insert or update, but when a user deletes a record I
can't figure out how to capture that user. 
I can't use system_user, that only shows the user name we created to
access the application.
Any ideas?
 
Betsy Powlen
Stanley Associates
3800 Fettler Park Drive
Dumfries, VA  22025
Office: (703) 441-4965
Cell:    (540) 498-0836
betsy.powlen.ctr at usmc.mil <blocked::mailto:betsy.powlen.ctr at usmc.mil> 
betsy.powlen at stanleyassociates.com