11.2 database audit

select distinct user_name from dba_stmt_audit_opts returns following users :

USER_NAME

-------------------------

SYSTEM

DBOPR

However when I query dba_audit_trail  for select statements executed yesterday, I see following user

USERNAME    ACTION_NAME   TIMESTAMP

-----------------    ---------------------    ------------------

APPSUSER1   SELECT               16-APR-17

APPSUSER1   SELECT               16-APR-17

APPSUSER1   SELECT               16-APR-17

Which view other than dba_stmt_audit_opts would contain information about appsuser1.