diff --git a/llm-service/app/routers/index/data_source/__init__.py b/llm-service/app/routers/index/data_source/__init__.py
index ec88985..59a5edd 100644
--- a/llm-service/app/routers/index/data_source/__init__.py
+++ b/llm-service/app/routers/index/data_source/__init__.py
@@ -172,4 +172,6 @@ def download_and_index(
                 embedding_model=models.get_embedding_model(),
                 chunks_vector_store=self.chunks_vector_store,
             )
+            # Delete to avoid duplicates
+            self.chunks_vector_store.delete_document(request.document_id)
             indexer.index_file(file_path, request.document_id)
diff --git a/llm-service/app/tests/routers/index/test_data_source.py b/llm-service/app/tests/routers/index/test_data_source.py
index 27051f9..e1b587b 100644
--- a/llm-service/app/tests/routers/index/test_data_source.py
+++ b/llm-service/app/tests/routers/index/test_data_source.py
@@ -77,6 +77,40 @@ def test_create_document(
         )
         assert len(vectors.nodes or []) == 1
 
+    @staticmethod
+    def test_double_create_document(
+        client: TestClient,
+        index_document_request_body: dict[str, Any],
+        document_id: str,
+        data_source_id: int,
+    ) -> None:
+        """Test POST /download-and-index."""
+        response = client.post(
+            f"/data_sources/{data_source_id}/documents/download-and-index",
+            json=index_document_request_body,
+        )
+
+        assert response.status_code == 200
+        assert document_id is not None
+
+        response = client.get(f"/data_sources/{data_source_id}/size")
+        assert response.status_code == 200
+        size1 = response.json()
+
+        response = client.post(
+            f"/data_sources/{data_source_id}/documents/download-and-index",
+            json=index_document_request_body,
+        )
+
+        assert response.status_code == 200
+        assert document_id is not None
+
+        response = client.get(f"/data_sources/{data_source_id}/size")
+        assert response.status_code == 200
+        size2 = response.json()
+
+        assert size2 == size1
+
     @staticmethod
     def test_delete_data_source(
         client: TestClient,