I agree with Jerry. It's fine grammatically, but it is unnecessarily 'wordy', so it doesn't read very smoothly. Also, it's not clear what 'took care of' means here. Perhaps 'He was careful to get rid of the body...'

There is nothing wrong with the sentence however you could shorten it up a lot by writing it like this: "He got rid of the body before the police got there."

That sentence is absolutely grammatically correct. :)

I agree with Su.Ki

Grammatically... It is correct. But I would prefer using the word "found" instead of "visited"