In this context, you may refer to the fillowing guidelene in the Handbook for Inquiry & Disciplinary Proceedings which could be accessed at https://dopt.gov.in/sites/default/files/Vigilance_Handbook-2013.pdf
CHAPTER – 14 FUNCTIONS OF INQUIRY OFFICER
21. Does the IO have power to enforce attendance of witnesses?
IO does not have power to enforce attendance of witnesses, except when an ad hoc notification in respect of the particular inquiry has been issued by the Central Government authorizing the Inquiring Authority to exercise powers specified in Section 5 of Departmental Enquiries (Enforcement of Attendance of Witnesses and Production of Documents) Act 1972.
22. What is to be done, if a listed witness does not turn up for inquiry?
In case a Government official who has been named as a witness in a departmental proceeding fails to turn up, the matter may be reported to the higher authorities of the witnesses. Para 91 of P&T Manual provides that refusal to appear as witnesses can be construed as sufficient cause for initiating disciplinary proceedings against him.
CHAPTER - 17 CONDUCT OF INQUIRY
35. What happens if a witness fails to turn up for examination?
A government servant summoned by the Inquiring Authority for tendering evidence in a disciplinary proceedings is bound to attend the same. Failure to do so will amount a misconduct. Therefore, if a witness fails to turn up for inquiry without proper justification the Inquiring Authority may report the matter to the controlling officer of the witness so that disciplinary action could be initiated.
The summons to the witness is required to be issued in the form as prescribed at Chapter 42