Invoking with a GET the REST URL

/org_identities.json?coid=2&search.identifier=some_string

causes a 500 server error and in the log file

2015-04-08 14:24:41 Error: [PDOException] SQLSTATE[42S22]: Column not found: 105
4 Unknown column 'CoPerson.co_id' in 'where clause'

Leaving out 'coid=N' from the query causes the error to not happen.