Learn Italian: Che l'ostaggio venga avvelenato dal complice? - Could the hostage be poisoned by the accomplice?

This is an independent subjunctive, often used for rhetorical questions or to express sudden doubt. Starting a question with Che followed by the subjunctive is an idiomatic Italian way to say 'Could it be that...?', 'Is it possible that...?', or 'What if...?'.

Why use venga (from venire) instead of sia (from essere) to form the passive voice here?

In Italian, venire is frequently used instead of essere to form the passive voice in simple tenses. This is done to emphasize the action itself rather than the resulting state. While sia avvelenato is grammatically correct, it could imply the state of being already poisoned, whereas venga avvelenato clearly focuses on the act of poisoning being carried out.

How do we know if the accomplice is male or female, since complice ends in '-e'?

Nouns ending in -e that refer to people are often the same for both genders. We can determine the gender by looking at the article. Here, the articulated preposition dal is a combination of da + il, meaning this specific accomplice is male. A female accomplice would be dalla complice.

Could I translate 'Could the hostage be...' using the conditional potrebbe instead of this Che structure?