I expect this that the case is going to get dismissed on technical grounds without addressing the core issue. If you are not directly charged with the specific offense, what is the limit of "destroying evidence" as its own crime?

  - If I rob a bank and then burn all of my planning materials after the crime - did I destroy evidence?
  - If I rob a bank, the police question me but do not charge me with anything. I then burn all of the planning materials - did I destroy evidence?
  - If I rob a bank, the police have a warrant to search my house in relation to an unrelated insurance scam across the street. Then I burn all of my bank heist materials - did I destroy evidence?

When the police are "just having a chat" and you later destroy all of your papers which might have been linked to a crime - isn't that fully within my rights to destroy my property? When do I have an explicit requirement to maintain my effects so the state can use it against me?

If I have a dash-cam in my car and it records me speeding - am I not allowed to overwrite the old footage? What if that dash-cam footage is the only thing that proves a crime were committed? Now I am forced to let my possessions testify against me.