I assume this is V7.0. In that case, every deleted document should show up in the new logging module in the configuration. Open up configuration, then go to "Protokollierungen" ("Protocols"). You should be able to select the File Cabinet there and see every change made to every document in this file cabinet, including deletions.
In older versions, this might be logged in the old log files on disk. See the logging configuration in the Desktop Administration for that.
Greetings from Germany,
Simon H. Hellmann
DocuWare System Consultant