Last time a fish tried to grant me a wish, I cut its head off, gut, filet, pan sear on med high till throughly cooked and seasoned with a side of fiddleheads. Wish granted.
There are a bunch of laws outlining how governments can collect evidence. Yhere are some methods that are illegal. If they used a method prohibited by law, the evidence is unusable. If the violation to obtain the evidence is severe enough the cop gets charged.
This is why you don't put empty pots on hot burners.