Creepy Riddles

Riddle 4

On a Sunday afternoon a man living in an old mansion all alone (except for his worky peeps) and was found dead with a gun in his hand.

The police were called, and they asked the three others who were there when he died. This is what they said:

The chef said: 'I was cooking dinner.'

The maid said: 'I was collecting the mail.'

And the butler said: 'I was setting up the dinner table.'

The police have no hesitation to arrest the maid. Why do they arrest her??