Any person who gives or offers or promises to give to any witness or person about to be called as a witness in any matter whatever, including contests before United States land officers or townsite commissioners, any bribe upon any understanding or agreement that the testimony of such witness shall be influenced, or who attempts by any other means fraudulently to induce any witness to give false testimony shall be guilty of a felony, but if the offer, promise, or bribe is in any way to induce the witness to swear falsely, then it shall be held to be subornation of perjury.