One hack that can be used is (This will only work for the recent modification) you can check the last modified time for the file, and cross check with the log-in times of the users. You might be able to narrow the list down.
This will only work for the recent modification.
- use
statcommand (ex: stat <file_name>, See this) - Find the
Modifytime - Use
lastcommand to see the log in history (see this) - Compare the log-in/log-out times with the file's
Modifytimestamp
This will not work all the time, but you can narrow the results down.