What's a word for when someone is wrong, and they know they're wrong, but they insist that they are right?
If someone does something and you know they did it, and they know they did it, but they keep telling everyone they didn't do it, and they go out of their way to try and convince others that they didn't do it.
(Example: Someone steals your dog. You know it's your dog. Your dog knows he's your dog. But the thief goes around saying its their dog and produces false receipts or photos (of other dogs), etc.)