What if the witness refuses to speak in an Internal Committee inquiry?

Problem Statement: 
As per CCTV evidence and the victim’s statements a witness was present when the incident occurred. But the witness feigns ignorance. This witness’s testimony is very crucial to the case. As an IC member, is there any action that can be taken?
 Witness’s Right to silence.
The Constitution of India guarantees every person right against self-incrimination under Article 20 (3): “No person accused of any offence shall be compelled to be a witness against himself”. It is well established that the Right to Silence has been granted to the accused by virtue of the pronouncement in the case of Nandini Sathpathy vs P.L.Dani, no one can forcibly extract statements from the accused, who has the right to keep silent, but only in the court of law. It is not clear if the accused can exercise his right to silence during interrogation by public servants. Interrogation techniques like narco-analysis, brain mapping and lie detection nullify the validity and legitimacy of the Right to Silence. But in 2010, the Supreme court found that narco-analysis, brain mapping and lie detector tests violate Article 20(3).
Reasons for witness to turn hostile or stay silent:
At the workplace, the reasons for a witness to turn hostile may be:

• Fear of retaliation.
• Fear of losing their job.
• Threat by the accused.
• Lack of awareness of the policy or process.
• Lack of trust in the committee or management.
• Absence of Witness Protection.
• Prolonged trials.

Hostile Witnesses: Judicial Remedy
For a situation like the Jessica Lal case, where witnesses refused to support the prosecution’s case, the committee has suggested the following measures:
1. Holding in-camera proceedings
2. Taking measures to keep identity of witness’s secret
3. Ensuring anonymity
4. Making arrangements to ensure their protection
5. Witnesses should be treated like guests of honour
6. They should be adequately compensated for spending money on travel and accommodation
7. Comfort, convenience and dignity of witness/es while giving their statements in the court of law, should be ensured
In Summary:

• A Witness can stay silent, if they wish to and cannot be forced. In such cases the, above judicial remedies may be followed to enhance the trust in the witness.
• A fine can be imposed or action can be taken on the witness, only if the witness says contradicting statements or retracts a statement made.
• Also, if the witness statement is proved to be intentionally false or malicious, then a strong action can be taken on the witness.

Ref:
https://en.wikipedia.org/wiki/Right_to_silence#India
http://www.legalservicesindia.com/article/article/hostile-witnesses-and-efficacy-of-law-1692-1.html