diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec58f05..d2dc915 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,14 +9,19 @@ This Changelog tracks changes to this project. The notes below include a summary
 - `fixed` for any bug fixes.
 - `security` in case of vulnerabilities.
 
+## 26 Apr 2023
+
+- `fixed` `_download_blob_bytes` should raise FileNotFoundError if the blob to download doesn't exist
+
 ## 19 Apr 2023
 
 - `changed` API/schemas bump for microbiome req reverse index
 - 
+
 ## 20 Mar 2023
 
 - `fixed` bug causing error on cloud issuing of cross-trial permissions
-  - this is interaction with accepted param types from API, so would need integrative testing
+- this is interaction with accepted param types from API, so would need integrative testing
 
 ## 24 Feb 2023
 
diff --git a/functions/util.py b/functions/util.py
index 4dc924e..8ed12ec 100644
--- a/functions/util.py
+++ b/functions/util.py
@@ -90,7 +90,7 @@ def _download_blob_bytes(object_name: str) -> bytes:
     bucket = storage_client.get_bucket(GOOGLE_ACL_DATA_BUCKET)
     blob = bucket.get_blob(object_name)
     if not blob:
-        FileNotFoundError(
+        raise FileNotFoundError(
             f"Could not find file {object_name} in {GOOGLE_ACL_DATA_BUCKET}"
         )
     return blob.download_as_string()
diff --git a/tests/functions/test_util.py b/tests/functions/test_util.py
index 37c562e..55f6848 100644
--- a/tests/functions/test_util.py
+++ b/tests/functions/test_util.py
@@ -2,6 +2,7 @@
 from unittest.mock import MagicMock
 
 import pytest
+from functions.settings import GOOGLE_ACL_DATA_BUCKET
 
 from tests.util import make_pubsub_event
 from functions import util
@@ -75,3 +76,35 @@ def test_get_blob_as_stream(monkeypatch):
     stream = util.get_blob_as_stream("", as_string=True)
     assert isinstance(stream, StringIO)
     assert stream.read() == blob_str
+
+
+mock_bucket = None
+
+
+class MockStorageClient:
+    def get_bucket(self, *args):
+        return mock_bucket
+
+
+def test_download_blob_bytes(monkeypatch):
+    global mock_bucket
+    mock_blob = MagicMock()
+    mock_blob.download_as_string.return_value = "expected blob contents"
+    mock_bucket = MagicMock()
+    mock_bucket.get_blob.side_effect = [
+        # first call checks that the proper exception is thrown for a missing object
+        None,
+        # second call checks that the contents are returned as expected
+        mock_blob,
+    ]
+
+    monkeypatch.setattr(util.storage, "Client", MockStorageClient)
+
+    object_name = "x/y/z"
+    with pytest.raises(
+        FileNotFoundError,
+        match=f"Could not find file {object_name} in {GOOGLE_ACL_DATA_BUCKET}",
+    ):
+        util._download_blob_bytes(object_name)
+
+    assert util._download_blob_bytes(object_name) == "expected blob contents"