In a sane world, that would be destruction of evidence. You shouldn’t be able to tell the court evidence exists and then destroy it before you let anyone else examine it.
Examined and secured. Having evidence in official custody should be a prerequisite for using it in an official capacity - or stuff like this happens.
You don’t have a right to fight an arrest warrant. But you do have a right to review the evidence that will be used against you during your trial.
I think prosecutors should go to jail if they keep their evidence in a building covered in kerosene and then "whoops" the evidence has gone up in flames.