What is the moral action if you accidentally download something* illegal?

*by something, I'm talking like in the following case:

Do you call the police and report it? What about the chance that they would still throw you into the slammer for possession of illegal images? Yes, that is not going to happen in 100% of the cases, but you should read how many people get the book thrown at them from doing nothing illegal, from a recent story about a woman being charged with illegally copying while videotaping a surprised birthday party at the theater before the movie actually started, she happened to get a few minutes of the opening commercials to the stories about the (underage) teenagers who are sent to jail for production of child pornography for taking pictures of themselves and sending it to a boyfriend.

So, considering that there is some chance, especially if the DA in your area is very idiotic, and you cannot afford a decent lawyer, to just pull your hard drive out and literally, physically destroy it, even if reporting the thing to the police has a chance of the police finding the one who is making those images or, if they can't find out who did it, at least stopping the spread of such material? Or is that being an paranoid idiot?

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Absolutely delete it right away. Possession is generally a strict liability crime, of which there might be no defense. Any prosecutor in their right mind would not seek to hold you liable you for this, if he or she believed you, but prosecutors have done crazier things.

Delete it, and if you feel some responsibility, you can point law enforcement to the source, without ever admitting that it was in your possession.

Shred (secure delete) the file immediately. Stuff like this is why I strongly suggest encrypting your drive.

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