A Preacher, a Lawyer, and a Doctor all go hunting

A preacher, a lawyer, and a doctor all do deer hunting.

They go for a few hours without seeing anything, and then they all spot an enormous deer grazing in a field.
They all excitedly shoot at it at the same time.
The deer immediately drops, but they only find one bullet hole.They argue and debate for hours over who shot the deer, each wanting it claim the trophy of a kill.
After much debate and getting nowhere, they decide to call their friend, who is a Wild Life Expert, to come and examine the deer.
They tell him where they all stood, that they shot it at the same time, and that it dropped immediately.
He looks at it for hours, and he keeps circling the deer, looking all over, and finally said:

“I know who shot the deer”

“Who?” They all asked eagerly.

“It was the preacher.”

The preacher jumps up and down and shouts for joy, while the other two are furious.

“How can you tell that just from looking at the bullet hole?!” They ask angrily

“Well it’s really very simple gentlemen.”
He says calmly. “If you look at the bullet hole, you can see that it goes inside one ear, and comes out the other”