An investigator has the powers conferred by section 171.
An investigator may also require a person who is neither the subject of the investigation ("the person under investigation") nor a person connected with the person under investigation—
to attend before the investigator at a specified time and place and answer questions; or
otherwise to provide such information as the investigator may require for the purposes of the investigation.
A requirement may only be imposed under subsection (2) if the investigator is satisfied that the requirement is necessary or expedient for the purposes of the investigation.
"Investigator" means a person appointed as a result of subsection (1) , (4) or (4B) of section 168.
"Specified" means specified in a notice in writing.