Real Dictionary

inquest
You can refer to an investigation by the people involved into the causes of a defeat or failure as an inquest.
countable noun: When an inquest is held, a public official hears evidence about someone's death in order to find out the cause.

inquest in American English
a judicial inquiry, as a coroner's investigation of a death
noun: a legal or judicial inquiry, usually before a jury, esp. an investigation made by a coroner into the cause of a death

inquest in British English
noun: an inquiry into the cause of an unexplained, sudden, or violent death, or as to whether or not property constitutes treasure trove, held by a coroner, in certain cases with a jury