diff --git a/jvector-base/src/main/java/io/github/jbellis/jvector/disk/SimpleMappedReader.java b/jvector-base/src/main/java/io/github/jbellis/jvector/disk/SimpleMappedReader.java
index 343da0370..c03e2a486 100644
--- a/jvector-base/src/main/java/io/github/jbellis/jvector/disk/SimpleMappedReader.java
+++ b/jvector-base/src/main/java/io/github/jbellis/jvector/disk/SimpleMappedReader.java
@@ -91,7 +91,7 @@ public int readInt() {
     @Override
     public void read(int[] ints, int offset, int count) {
         for (int i = 0; i < count; i++) {
-            ints[i] = mbb.getInt();
+            ints[offset + i] = mbb.getInt();
         }
     }