What Evil Is This?

Yesterday, a vacationing friend sent me the picture above of a snake which had been roused from it's slumber inside an outside storage facility.

She wasn't sure if the snake was poisonous but she informed me the snake was no longer with us because her husband decapitated it with a pool net. The home owner told her the snake was harmless, but my friend and I agreed the reptile's markings were too elaborate to take any chances.

Scott Shepherd informed me on-air this morning that annihilating non-poisonous snakes should be avoided if at all possible since they help control the vermin population. He gave me a few tips for discerning the difference but I'm pretty sure I'm not going to stick around long enough to determine the shape of the snake's pupils.

First, do you know what type of snake this WAS and how can I tell the difference in the future?