The Buried Truth: Professional Investigator Shoko Jinguji, Tsumugi Akari SHKD-836

A mysterious series of murders by a couple leaves only a trace of injection marks on the victims' heads as a clue at the scene. Investigator Shoko, relying on her intuition, gets closer to the truth, only to receive orders to halt the investigation. She continues her investigation alone... and is about to encounter danger.