diff --git a/Core/src/org/sleuthkit/autopsy/modules/fileextmismatch/FileExtMismatchIngestModule.java b/Core/src/org/sleuthkit/autopsy/modules/fileextmismatch/FileExtMismatchIngestModule.java
index 52a713eade..c9b25cf8d6 100644
--- a/Core/src/org/sleuthkit/autopsy/modules/fileextmismatch/FileExtMismatchIngestModule.java
+++ b/Core/src/org/sleuthkit/autopsy/modules/fileextmismatch/FileExtMismatchIngestModule.java
@@ -24,6 +24,7 @@ import java.util.Set;
 import java.util.logging.Level;
 import org.openide.util.NbBundle;
 import org.openide.util.NbBundle.Messages;
+import org.python.icu.text.MessageFormat;
 import org.sleuthkit.autopsy.casemodule.Case;
 import org.sleuthkit.autopsy.casemodule.NoCurrentCaseException;
 import org.sleuthkit.autopsy.coreutils.Logger;
@@ -142,9 +143,13 @@ public class FileExtMismatchIngestModule implements FileIngestModule {
             addToTotals(jobId, System.currentTimeMillis() - startTime);
 
             if (mismatchDetected) {
+                String justification = MessageFormat.format("File has an extension of {0} but mime type is {1}", 
+                        abstractFile.getNameExtension(), detector.getMIMEType(abstractFile));
+                
                 // add artifact               
                 BlackboardArtifact bart = abstractFile.newAnalysisResult(
-                        BlackboardArtifact.Type.TSK_EXT_MISMATCH_DETECTED, LIKELY_NOTABLE_SCORE, null, null, null, Collections.emptyList())
+                        BlackboardArtifact.Type.TSK_EXT_MISMATCH_DETECTED, LIKELY_NOTABLE_SCORE, 
+                        null, null, justification, Collections.emptyList())
                         .getAnalysisResult();
 
                 try {