"Smiles" joke

Three smiling corpses are lying in a morgue in Arkansas,
and a detective goes into the coroner's to find the
causes of death. The coroner points to the first dead man.
"This is Cletus," he says. "He died of shock after winning
20 million on the lottery."
He then moves on to the second smiling corpse. "This is Bo,"
the coroner says with a grin. "He died while doing 'it' with
Trudy-May."
Finally he moves on to the last smiling corpse. "This is
Roscoe," says the coroner. "He died after being struck by
lightning."
"Well," asks the detective, "Why in hell was the fool smiling?"
"Oh," says the coroner. "He thought he was having his picture
taken."