Originally Posted by
pmocek
Yes. I powered the camera on, saw its indication that images and videos were gone, powered off, removed card, mounted the card read-only in my laptop, made a bit-for-bit copy, copied that data to a secure, off-site location, and stored the card somewhere safe.
You may want to show that copy to somebody who knows more about directory formats than we do. Many cameras have files in the filesystem that contain information such a next picture number. When the card is erased, that file may be modified or created and there may be a timestamp there.