major cop groaner

Two police officers respond to a crime scene behind a grocery store. The homicide detective is already there.

"What happened?" asks the first officer.

"Male, about twenty-five, covered in Raisin Bran and dead as a doornail."

"Good grief," says the second officer. "Didn't we have one covered in Frosted Flakes yesterday? And Captain Crunch last week?"

"You're right. I'm afraid," said the detective as he took a drag from his cigar, "this is the work of a cereal killer."