diff --git a/endpoints/api/organization.py b/endpoints/api/organization.py
index ae43a86fb..0ac57b7c6 100644
--- a/endpoints/api/organization.py
+++ b/endpoints/api/organization.py
@@ -18,6 +18,7 @@ from auth.auth_context import get_authenticated_user
 from auth import scopes
 from data import model
 from data.billing import get_plan
+from util.names import parse_robot_username
 
 
 logger = logging.getLogger(__name__)
@@ -391,7 +392,14 @@ class OrganizationMember(ApiResource):
       # Lookup the user's information in the organization.
       teams = list(model.team.get_user_teams_within_org(membername, organization))
       if not teams:
-        raise NotFound()
+        # 404 if the user is not a robot under the organization, as that means the referenced
+        # user or robot is not a member of this organization.
+        if not member.robot:
+          raise NotFound()
+
+        namespace, _ = parse_robot_username(member.username)
+        if namespace != orgname:
+          raise NotFound()
 
       repo_permissions = model.permission.list_organization_member_permissions(organization, member)