whodunit
US /ˌhuːˈdʌn.ɪt/
UK /ˌhuːˈdʌn.ɪt/

1.
giallo, romanzo poliziesco
a story or play about a murder in which the identity of the murderer is not revealed until the end
:
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She loves reading classic whodunits by Agatha Christie.
Le piace leggere i classici gialli di Agatha Christie.
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The movie was a gripping whodunit with many twists.
Il film era un avvincente giallo con molti colpi di scena.