noun
independent committee; third-party panel
A committee established by an organization but composed of external, neutral members to investigate issues or make impartial decisions.
不祥事を受けて、会社は第三者委員会を設置した。
In response to the scandal, the company set up an independent committee.
第三者委員会の調査報告書が公表された。
The investigation report of the third-party panel was released.
調査委員会 is a general investigation committee, which may be internal; 第三者委員会 specifically emphasizes independence from the parties involved.
Compound of 第三者 (third party) + 委員会 (committee).