"I am suspected of helping the police."
Translation:Saya diduga membantu polisi.
I don't think an English speaker would say that - and the Bahasa doesn't include "jika" or "kalau" here, common words for "if". The Bahasa is in the progressive tense, your proposed translation puts into the present or future conditional. This is useful https://en.wikibooks.org/wiki/Indonesian/Tenses