diff --git a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/EmailMessage.java b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/EmailMessage.java
index 9aee14ede8..7b0b2eb30e 100644
--- a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/EmailMessage.java
+++ b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/EmailMessage.java
@@ -47,7 +47,7 @@ class EmailMessage {
     private long id = -1L;
     private String messageID = "";
     private String inReplyToID = "";
-    private String references = "";
+    private List<String> references = null;
 
     boolean hasAttachment() {
         return hasAttachment;
@@ -226,7 +226,7 @@ class EmailMessage {
      * 
      * @return reference list or empty string if non is available.
      */
-    String getReferences() {
+    List<String> getReferences() {
         return references;
     }
     
@@ -235,7 +235,7 @@ class EmailMessage {
      * 
      * @param references 
      */
-    void setReferences(String references) {
+    void setReferences(List<String> references) {
         this.references = references;
     }
 
diff --git a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/MboxParser.java b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/MboxParser.java
index 402a2090ec..f2294349c8 100644
--- a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/MboxParser.java
+++ b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/MboxParser.java
@@ -181,14 +181,26 @@ class MboxParser {
         email.setLocalPath(localPath);
         email.setMessageID(msg.getMessageId());
         
-        Field field =  msg.getHeader().getField("in-reply-to"); //NON-NLS
+        Field field = msg.getHeader().getField("in-reply-to"); //NON-NLS
+        String inReplyTo = null;
+
         if (field != null) {
-            email.setInReplyToID(field.getBody());
+            inReplyTo = field.getBody();
+            email.setInReplyToID(inReplyTo);
         }
-        
+
         field = msg.getHeader().getField("references");
-        if (field != null ) {
-            email.setReferences(field.getBody());
+        if (field != null) {
+            List<String> references = new ArrayList<>();
+            for (String id : field.getBody().split(">")) {
+                references.add(id.trim() + ">");
+            }
+
+            if (!references.contains(inReplyTo)) {
+                references.add(inReplyTo);
+            }
+
+            email.setReferences(references);
         }
 
         // Body
diff --git a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/PstParser.java b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/PstParser.java
index 251d9b67d0..81d26b6609 100644
--- a/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/PstParser.java
+++ b/thunderbirdparser/src/org/sleuthkit/autopsy/thunderbirdparser/PstParser.java
@@ -193,13 +193,24 @@ class PstParser {
         email.setSubject(msg.getSubject());
         email.setId(msg.getDescriptorNodeId());
         email.setMessageID(msg.getInternetMessageId());
-        email.setInReplyToID(msg.getInReplyToId());
+        
+        String inReplyToID = msg.getInReplyToId();
+        email.setInReplyToID(inReplyToID);
 
         if (msg.hasAttachments()) {
             extractAttachments(email, msg, fileID);
         }
         
-        email.setReferences(extractReferences(msg.getTransportMessageHeaders()));
+        List<String> references = extractReferences(msg.getTransportMessageHeaders());
+        if (inReplyToID != null && !inReplyToID.isEmpty()) {
+            if (references == null) {
+                references = new ArrayList<>();
+                references.add(inReplyToID);
+            } else if (!references.contains(inReplyToID)) {
+                references.add(inReplyToID);
+            }
+        }
+        email.setReferences(references);
 
         return email;
     }
@@ -349,28 +360,33 @@ class PstParser {
     
     /**
      * Returns the references value from the email header.
-     * 
+     *
      * @param emailHeader
-     * @return 
+     *
+     * @return A list of message-IDs
      */
-    private String extractReferences( String emailHeader ){
+    private List<String> extractReferences(String emailHeader) {
         Scanner scanner = new Scanner(emailHeader);
         StringBuilder buffer = null;
-        while(scanner.hasNextLine()) {
+        while (scanner.hasNextLine()) {
             String token = scanner.nextLine();
-            
-            if( token.matches("^References:.*") ) {
+
+            if (token.matches("^References:.*")) {
                 buffer = new StringBuilder();
-                buffer.append((token.substring(token.indexOf(":")+1)).trim());
-            } else if ( buffer != null ) {
-                if(token.matches("^\\w+:.*$")){
-                    return buffer.toString();
+                buffer.append((token.substring(token.indexOf(":") + 1)).trim());
+            } else if (buffer != null) {
+                if (token.matches("^\\w+:.*$")) {
+                    List<String> references = new ArrayList<>();
+                    for (String id : buffer.toString().split(">")) {
+                        references.add(id.trim() + ">");
+                    }
+                    return references;
                 } else {
                     buffer.append(token.trim());
                 }
             }
         }
-        
-        return "";
-    }       
+
+        return null;
+    }    
 }