diff --git a/benchexec/tools/concurrentwitness2test.py b/benchexec/tools/concurrentwitness2test.py
index 52f81f85c..c00dee125 100644
--- a/benchexec/tools/concurrentwitness2test.py
+++ b/benchexec/tools/concurrentwitness2test.py
@@ -40,7 +40,7 @@ def determine_result(self, run):
             if "Verdict: SOMETIMES" in line or "Verdict: ALWAYS" in line:
                 return result.RESULT_FALSE_REACH
             elif "Verdict: NEVER" in line:
-                return result.RESULT_TRUE_PROP
+                return result.RESULT_ERROR + "(ineffective  witness)"
             elif "Verdict: TIMEOUT" in line:
                 return result.RESULT_TIMEOUT + "(inner)"
             elif "Verdict: Unknown error" in line: