they always hang round with a certain girl.
Ask her. She will either tell you the truth or tell you it is none of your damn business. If so, then it isn't :)
- You CAN'T tell if someone is a lesbian or not unless they tell you. I don't really see how it's anyone's business, unless of course it's someone you're (( generally speaking )) interested in. Even still, you should either ask her or wait for her to tell you. There's no specific image or way of knowing.