Yin and Yang

Detective Yang came into a case where a sex offender was killed by being thrown out the window along with bruises and broken bones. Yang noticed the patterns of the bruises on the body and how the broken bones weren't just from the fall. Like Yang, the murderer was a martial artist, a skilled one as Yang had identified according to the patterns of the bruises. Yang must capture the culprit, but he has a feeling more will be coming to than just one expert, martial artist murderer.