In the Watchtower online website, I did a search for the words false prophet and filtered it for scriptures only from the Bible which brought up zilch in the way of results.
I did a Google advanced search for the same thing and it brought up the scripture I needed which happens to be Deuteronomy chapter 18:20-22 which reads...
20 “‘If any prophet presumptuously speaks a word in my name that I did not command him to speak or speaks in the name of other gods,
that prophet must die.+
21 However, you may say in your heart: “How will we know that Jehovah has not spoken the word?”
22 When the prophet speaks in the name of Jehovah and the word is not fulfilled or does not come true, then Jehovah did not speak that word.
The prophet spoke it presumptuously. You should not fear him.’
I guess my point being that they do post all kinds of incriminating things on their website but they don't make it very easy for you to find.
From now on Google is going to be my go-to to search their website.