I have no idea where this poster lives but Choctaw is 30 miles from where I live in East Norman and I live about 4-5 miles from West Norman. It takes 45 minutes to get to Choctaw from North North High School if not a little longer than that.
There is no way this could have been heard in West Norman -- zero, zip, nada. Police cannot find burn marks anywhere but will look again in the morning.
That's definitely weird to say the least... I wonder if they're looking in the wrong area perhaps? Must've gotten a phone call or something if police cordoned off the school in Choctaw though.
I Can't imagine how the person could've heard it that far away. Perhaps there was a crash or something on the Interstate near the same time?