15.—(1) This regulation applies where the matter is to be investigated in accordance with regulation 14.
(2) The appropriate authority must appoint a person to investigate the matter.
(3) No person may be appointed to investigate a matter under this regulation—
(a)unless they have an appropriate level of knowledge, skills and experience to plan and manage the investigation;
(b)if they are an interested party;
(c)if they work, directly or indirectly, under the management of the officer concerned, or
(d)in a case where the officer concerned is a senior officer, if they are—
(i)the chief officer of police of the police force concerned;
(ii)a member of the same police force as the officer, or where the officer is a member of the metropolitan police force, serving in the same command as the officer, or
(iii)a designated police volunteer serving in that force.
(4) The reference in paragraph (3)(d)(ii) to a member of the police force includes a reference to a special constable appointed for the area of that force and a police staff member serving in that force.