This is Joanna Yeates/Chris Jefferies all over again isn't it? 
We know nothing about this case other than the very little information that has been released to the press. All we know is that a woman left a nightclub with a man and now she is dead. 
But it's all too easy to speculate, and reality is that there is so little information and so much which doesn't add up - even from the point of view of what her friends have said, that it's possible anything could have happened.
And given the man in the flat was the last to presumably have seen her alive, it stands to reason that he would have to be questioned by the police.
But nothing else can be assumed - even from what her friends have said. Because fact remains she left the nightclub willingly and was seen on cctv getting into his car. Perhaps she knew him. Perhaps she did actually like one night stands but perhaps came from a conservative background and therefore didn't talk about her sex life - even to her friends. Perhaps she'd had a falling out with her friends and was offered comfort by this man, hence why she left without her coat or saying goodbye. but her friends didn't want to admit to that because she was now missing.
The police have to follow due process. if the man detained is the man she left with,and if there is enough evidence, then he will be charged. But we simply cannot presume guilt based on the fact that he was ugly and that no woman would have slept with him willingly. There are plenty of "ugly" (what is ugly anyway?) men with attractive partners and vice versa. it's all subjective.