Can an Ex-Employee be asked to participate in Domestic Enquiry as a Witness?

Dear All,
Can you please advise whether an organization can ask an ex-employee to participate as a witness in a domestic enquiry? And, if the ex-employee participates in the enquiry, can the delinquent enquiry object to his participation on the ground that the ex-employee is no longer in the organization so can not participate?
Thanks and kind regards
Hasib

As an Independent Witness, any Person with knowledge of the Incident/occurrence relating and relevant to the Charge/allegation leveled which is under consideration of the Inquiry Officer or Inquiry Committee, Can appear and Testify during Inquiry Proceedings.
Where is the Question of anyone objecting to such a Person or Persons appearing as Witness and it is up to the Inquiry Officer and or the Inquiry Committee to decide whether the Testimony recorded during the ongoing Inquiry Proceedings can be given Credence or Not?
However, the Objection be Recorded in the Order Sheet with valid reasons as why the Objection was considered yet not acceded to by the Inquiry Officer Committee.
Universal Principles of Natural Justice applicable to such Internal Inquiries state that..."Hear the Other Side...."/the other side must be heard....."
Kritarth Team of Professional Inquiry Experts
24th July 2018