Officer Maori didn't wait for the autopsy report to be finished before he headed back to the police station. A report like this would indeed not be ready in just a day or two. Since he couldn't immediately obtain the relevant clues, Officer Maori could only start his investigation at the station with the available leads.
Fortunately, it wasn't entirely without clues— at least he now knew that the victim in the acid disposal case was a man, and the victim in the burning case was a woman, contrary to the genders initially suggested by the cases.
