水落石出

经过警方历时半年的深入调查，这起悬案的真相终于水落石出。

jīng guò jǐng fāng lì shí bàn nián de shēn rù diào chá, zhè qǐ xuán àn de zhēn xiàng zhōng yú shuǐ luò shí chū.

After an in-depth investigation by the police that lasted for half a year, the truth of this unsolved case finally came to light.