diff --git a/csharp/extractor/Semmle.Util/ProcessStartInfoExtensions.cs b/csharp/extractor/Semmle.Util/ProcessStartInfoExtensions.cs
index e4468cc9c402..fb900c79f9d9 100644
--- a/csharp/extractor/Semmle.Util/ProcessStartInfoExtensions.cs
+++ b/csharp/extractor/Semmle.Util/ProcessStartInfoExtensions.cs
@@ -27,7 +27,7 @@ public static int ReadOutput(this ProcessStartInfo pi, out IList<string> stdout,
                         return;
                     }
 
-                    onOut?.Invoke(e.Data);
+                    onOut?.Invoke($"[PID: {process.Id}] {e.Data}");
                     @out.Add(e.Data);
                 });
             }