diff --git a/java/src/net/sf/samtools/BAMFileReader2.java b/java/src/net/sf/samtools/BAMFileReader2.java
index 54a23b090..51030e534 100644
--- a/java/src/net/sf/samtools/BAMFileReader2.java
+++ b/java/src/net/sf/samtools/BAMFileReader2.java
@@ -565,7 +565,10 @@ class BAMFileReader2
          * Closes down the existing iterator.
          */
         public void close() {
-            wrappedIterator.close();
+            if (this != mCurrentIterator) {
+                throw new IllegalStateException("Attempt to close non-current iterator");
+            }
+            mCurrentIterator = null;
         }
 
         /**