diff --git a/sort_certificate.py b/sort_certificate.py
index 582bec7..98fb7b0 100755
--- a/sort_certificate.py
+++ b/sort_certificate.py
@@ -176,7 +176,15 @@ def find_root(x509_objects, root_issuers):
     '''
     Find a suitable anchor by finding the intermediate that was signed by root
     '''
-    root_cert = root_issuers[str(x509_objects[-1].get_issuer())]
+    root_cert = None
+    for x509_object in reversed(x509_objects):
+        if str(x509_object.get_issuer()) in root_issuers:
+            root_cert = root_issuers[str(x509_object.get_issuer())]
+            break
+    if not root_cert:
+        raise CertificateComponentException('Unable to find a suitable '
+                                            'trusted root certificate '
+                                            'for bundle')
     logging.debug('Retrieved root certificate %s', root_cert.get_subject())
     return root_cert