Late Friday night a group of people were hanging out in the park getting drunk. As the night went on, all but two left. Those two were sitting on top the shallow end of the pool, as they were about to leave, one noticed that the coping block he was sitting on was loose. So he pulled it off and threw it into the pool where it shattered. He then preceded to pull off more pieces and throw them in all directions, having them break apart at impact in the snakerun and street sections. After doing that to about 16 pieces of coping, he couldn't pull off the 17th piece and just decided to leave.
The graffiti left behind, which was rumored in earlier reports to be done by the vandals, was a separate act, not done by the person who tore up the pool.