diff --git a/km3io/offline.py b/km3io/offline.py
index 4a62e37f165f0ad111671fa10b9c0daaa7d4a0d1..67612e886167eb75a8e35a2758aa98eccce3efc4 100644
--- a/km3io/offline.py
+++ b/km3io/offline.py
@@ -67,7 +67,7 @@ class OfflineReader(EventReader):
             "dir_x": "mc_trks.dir.x",
             "dir_y": "mc_trks.dir.y",
             "dir_z": "mc_trks.dir.z",
-            "E": "mc_trks.E"
+            "E": "mc_trks.E",
             # "status": "mc_trks.status",  # TODO: check this
             # "mother_id": "mc_trks.mother_id",  # TODO: check this
             "type": "mc_trks.type",