Crime scene: 162 mystery solving puzzles to find out who the murderer is

Chapter 58 He is still her
Laura, a fashion model from Liverpool, lives a dissolute life, is gay and flirts with men.One Sunday morning, she was found dead in the bathroom after being hit in the head with a Coke bottle.According to the neighbor’s report: “Since last night, people have been playing in Laura’s room. At dawn today, I heard arguing, but I couldn’t tell whether it was a man or a woman.” Lady lover, how to determine the gender of the murderer?
Police officer Rosen pointed to the toilet bowl with the cover and seat upturned and said: "Just looking at the scene, you can tell whether the murderer is a man or a woman."

How did Rosen judge?

[Answer] It is of course a man who uses a flush toilet without a seat cushion, so the murderer must be found among Laura's male lovers.

(End of this chapter)