Primary: Press the button for a quick slash attack.
Secondary: When the button is held down, Chuck stabs the target zombie 4 times in the chest as violins play in a horror music style reminiscent of the music played in Psycho's famous Shower Scene, awarding 20 PP points, and covers Chuck with a large amount of blood.
The music played during the secondary attack is from a Hitchcock film called "Psycho", as a person is stabbed with a large knife, the same iconic sounds play in the movie.
There is a Chef Knife hidden in the Safe House in Case Zero, back in the store area, on top of a shelf. Jump up on the shelf near the door to find the Knife.
In Dead Rising, the chef knife was called a Cleaver and didn't have a heavy attack.