Here's the answer:
“사건은 경찰에 의해 해결되었어요”
Watch a real native speaker say it:
Here's how it sounds in a textbook:
Fun fact: the hundreds of thousands of people learning Korean with Memrise get this phrase correct 94.15% of the time!
Fun fact: the hundreds of thousands of people learning Korean with Memrise get this phrase correct 94.15% of the time!