"Informerede du politiet?"

Translation: Did you inform the police?

[AlexYoung12]

Why is "have you informed the police" wrong?

[RyagonIV]

Your sentence is a different tense, namely present perfect (have + participle). Asked here is simple past, though. Your sentence would be translated as (if I'm not mistaken) "Har du informeret politiet?"

[StripyStockings]

Why is "You informed the police?" not accepted?

[hoyastang]

I agree this should be accepted. It is proper English grammar and it means the same exact thing.

[epac-mcl]

StripyStockings: Although the practise of dropping "Did…" in such a question is very common in English, at least in the UK, your answer should have been "You inform the police?" This has been accepted many times by DUO.
"You informed the police? would be short for "Did you informed the police?", and one can't say that.

[RyagonIV]

This is either not the right grammar (in an English question without a question word you need to start with a form of 'to do', so: "Did you inform the police?") or it'd carry a different meaning.

[Isaac_Luna_]

She sounds as though she committed a crime.

[fred371888]

'Have you informed the police' means the same as 'did you inform the police'!