It is a brunette, a redhead and a blonde who burglar a supermarket.
Suddenly, they hear noise and hide in three sacks of potatoes. A policeman advances to the first bag and kicks in. The redhead is "Meow, meow ...".
Then the policeman advances towards the second: the brunette makes "Woof, woof ...".
Finally the policeman advances to the third bag and also gives a shot in it. The blonde makes "Potato, potato ...".