Wednesday night, Hays County officials briefly closed down RM 3237 in Wimberley while they -- along with the Austin P.D. bomb squad investigated what they eventually determined to be an explosive device containing C-4. That's an illegal military grade explosive that the public can't get.
They eventually detonated the device to render it safe.
Many of the neighbors we spoke with seem to have a good idea of who is responsible -- a survivalist that owns the property next to the hill.
Apparently the man is constantly scaring people by walking up and down the road in fatigues carrying firearms.
One lady who wants to stay anonymous lives near the cave and was inside her house when it was detonated.
"My goodness, it was...I've never been that close to a big boom like that, it was a serious event. Pictures fell off the wall, someone across the creek who is much further away than our house had windows break...it was a serious explosion," she said.
Hays County hasn't given us much more information on the explosives and they told us no one has been arrested yet.
Several of the neighbors we spoke with said they know why...the survivalist is already in jail...for a different reason. And they're hoping he stays in there this time.