Strange cats in my house

by erica viljoen
(south africa)

Strange cats in my house

I have strange cats in my house and I hope some one can help. I do have 2 female cats which are always home or in the garden. But at night strange cats is coming in the house and pee and mark in the house their space. And eat all my cats food. could some one give me some advice what to do to keep these strange cat's out. I can't close the windows completely because then my cat's can't go out. please I'm tired of having this cat pee smell in my house.