Simple answer... I believe that fellow has seen enough transgender people in his community to know what one is. I believe the police are obligated to report whatever sex they were given from the victim. I believe that the police would be obligated to keep from commenting on the case to the public if they knew the "it" was an "it". This is a PC world now days.
The police are required to report the info on the victim. There is no being polite on official reports.