I have a security group hanging around from a tenant that was deleted and I'm not able to delete it because it says its in use. i.e.

# neutron security-group-show d6bd5785-1be0-44e4-801d-6aa72d305d22
+----------------------+--------------------------------------+
| Field                | Value                                |
+----------------------+--------------------------------------+
| description          | default                              |
| id                   | d6bd5785-1be0-44e4-801d-6aa72d305d22 |
| name                 | default                              |
| security_group_rules |                                      |
| tenant_id            | 6267b8d549e94bd1806a32f8186f224d     |
+----------------------+--------------------------------------+

# neutron security-group-delete d6bd5785-1be0-44e4-801d-6aa72d305d22
Conflict (HTTP 409) (Request-ID: req-eaa6b9d5-e77e-42d8-a71f-d760640daea9)

# grep req-eaa6b9d5-e77e-42d8-a71f-d760640daea9 /var/log/neutron/server.log
2016-01-15 15:15:24.234 52761 INFO neutron.api.v2.resource [req-eaa6b9d5-e77e-42d8-a71f-d760640daea9 None] delete failed (client error): Security Group d6bd5785-1be0-44e4-801d-6aa72d305d22 in use.
2016-01-15 15:15:24.238 52761 INFO neutron.wsgi [req-eaa6b9d5-e77e-42d8-a71f-d760640daea9 None] 192.168.200.2 - - [15/Jan/2016 15:15:24] "DELETE /v2.0/security-groups/d6bd5785-1be0-44e4-801d-6aa72d305d22.json HTTP/1.1" 409 351 0.419005

I've looped through the ports, networks, and instances looking for that tenant_id trying to find what could be using it and I don't see anything with that tenant_id.

So how do I find what is using it to be able to delete this security group?