I would borrow a humane cat trap from the humane society if you can. I know how your friend feels, Tiger went missing for 4 days.
What a friend suggested to me is put canned tuna(with oil) or some smelly cat food(so she smells it) and litter in a box and of course with a bowl of water and another box with like a warm blanket and 2 things with her scent on it(tell her to rub it on her arm or something) and that would be a better chance to get her back. Put lost ads up around her neighborhood.

Tiger was in the area, so she is probably in the area. I will pray that her kitty comes home, I was heartbroken when Tiger went missing and I did everything I could. Sending lots of positive vibes to you and your friend that her kitty is found safe and sound. (((((hugs)))))