A fact-finding investigation committee was set up to look into the cause of the incident.
Literal
Incident [attributive-の] cause [object-を] investigate [in-order-to-ために] actual-situation-investigation-committee [subject-が] was-made-[passive-れた].
News reporting. 取り調べる ('to investigate, to interrogate') is the standard verb for law-enforcement or official investigations, also used for police interrogations. 実情調査 ('actual-situation investigation' = fact-finding) is a kango compound. 委員会 ('committee') is a standard institutional term. The passive 作られた removes the agent, treating the committee's formation as a reportable fact.