That is crazy. That is like here in my town. My dad is an avid golfer and he said there is a pond at the golf course and he noted that in the past few years the pond has grown lots with gold fish. He thinks someone didn't want the their gold fish and threw it in there. But who knows. They are not Koi but gold fish.
Anybody remembers when in LA a policeman dropped his too big pet alligator in a lake? It took two years to get the animal and take it to the zoo, they named him Reggie and he escaped from the zoo once but he is there again.
I'm from Europe, Hungary and it happened once there also but the alligator died in winter time.
There are so many careless or just simply stupid people out there.