JPC (Joint Parliamentary Committee) is generally constituted out of MPs to probe a controversial national important matter (usually a scam, irregularity etc.). Demand for a JPC is raised by the opposition, which the ruling party willingly or unwillingly may agree. It is tried to accomodate MPs from all major political parties usually in the ratio of their strength in the house. Naturally the persons who become a part of the committee become important, if they are not already so. The committee examines in detail the documentary evidences, the persons involved. They can call the concerened officers, ministers etc. to ascertain the facts. The committee usually is given a time frame which may be extended, if required. In the end, the committee tables its report and recommodations in the parliament for discussion and subsequent action to be taken.
Regards,
Shiv Parihar