Evening and Morning Star 2:105; “The only way of ascertaining a true prophet, is to compare his prophecies with the ancient word of God, and see if they agree, and if they do and come to pass, then certainly he is a true prophet: For it is not possible that the Lord will suffer FALSE prophets, to bring forth the truth, moved upon by the Holy Ghost, for it is written that the Holy Ghost dwelleth not in unholy temples. By their fruits shall they be known.”
Jeremiah 23:32-40; “Behold, I am against them that prophesy false dreams, saith the LORD, and do tell them, and cause my people to err by their lies, and by their lightness; yet I sent them not, nor commanded them: therefore they shall not profit this people at all, saith the LORD.” (Also see vs. 33-40.)
Actually bad people do tell the truth at times or they’ll give you part of the truth mixed with a healthy dose of lying.