diff --git a/muranoapi/api/v1/sessions.py b/muranoapi/api/v1/sessions.py
index 6ba243a3..a1e0b47d 100644
--- a/muranoapi/api/v1/sessions.py
+++ b/muranoapi/api/v1/sessions.py
@@ -48,6 +48,11 @@ class Controller(object):
         unit = get_session()
         session = unit.query(Session).get(session_id)
 
+        if session is None:
+            log.error('Session <SessionId {0}> is not found'
+                      ''.format(session_id))
+            raise exc.HTTPNotFound()
+
         if session.environment_id != environment_id:
             log.error('Session <SessionId {0}> is not tied with Environment '
                       '<EnvId {1}>'.format(session_id, environment_id))
@@ -98,6 +103,11 @@ class Controller(object):
         unit = get_session()
         session = unit.query(Session).get(session_id)
 
+        if session is None:
+            log.error('Session <SessionId {0}> is not found'
+                      ''.format(session_id))
+            raise exc.HTTPNotFound()
+
         if session.environment_id != environment_id:
             log.error('Session <SessionId {0}> is not tied with Environment '
                       '<EnvId {1}>'.format(session_id, environment_id))