Actually hindsight is 20/20. After the first killing and watching the video of him walking I thought it might be a woman. I don't know why I thought that except maybe power of suggestion that PC's given that said it could be a man or a woman and I began looking at the video differently. I don't know.
But after I realized it was a man the only thing that kept popping into my head was the fact that he is a sharp dresser, well put together, cares about his appearance, takes care of his clothing, like a woman. How he looked really mattered to him.
That is mainly what threw me off even though my own brother (rip) was like that too. My brother would never leave the house looking like a bum, he even pressed his jeans. He was high maintenance for a man and I loved it. That's what HD reminded me of initially after dismissing the female aspect of his appearance.